balmet.com

wp-db.php (106095B)

---

 <?php
 /**
  * WordPress database access abstraction class
  *
  * Original code from {@link http://php.justinvincent.com Justin Vincent (justin@visunet.ie)}
  *
  * @package WordPress
  * @subpackage Database
  * @since 0.71
  */
 
 /**
  * @since 0.71
  */
 define( 'EZSQL_VERSION', 'WP1.25' );
 
 /**
  * @since 0.71
  */
 define( 'OBJECT', 'OBJECT' );
 // phpcs:ignore Generic.NamingConventions.UpperCaseConstantName.ConstantNotUpperCase
 define( 'object', 'OBJECT' ); // Back compat.
 
 /**
  * @since 2.5.0
  */
 define( 'OBJECT_K', 'OBJECT_K' );
 
 /**
  * @since 0.71
  */
 define( 'ARRAY_A', 'ARRAY_A' );
 
 /**
  * @since 0.71
  */
 define( 'ARRAY_N', 'ARRAY_N' );
 
 /**
  * WordPress database access abstraction class.
  *
  * This class is used to interact with a database without needing to use raw SQL statements.
  * By default, WordPress uses this class to instantiate the global $wpdb object, providing
  * access to the WordPress database.
  *
  * It is possible to replace this class with your own by setting the $wpdb global variable
  * in wp-content/db.php file to your class. The wpdb class will still be included, so you can
  * extend it or simply use your own.
  *
  * @link https://developer.wordpress.org/reference/classes/wpdb/
  *
  * @since 0.71
  */
 class wpdb {
 
 	/**
 	 * Whether to show SQL/DB errors.
 	 *
 	 * Default is to show errors if both WP_DEBUG and WP_DEBUG_DISPLAY evaluate to true.
 	 *
 	 * @since 0.71
 	 * @var bool
 	 */
 	public $show_errors = false;
 
 	/**
 	 * Whether to suppress errors during the DB bootstrapping. Default false.
 	 *
 	 * @since 2.5.0
 	 * @var bool
 	 */
 	public $suppress_errors = false;
 
 	/**
 	 * The error encountered during the last query.
 	 *
 	 * @since 2.5.0
 	 * @var string
 	 */
 	public $last_error = '';
 
 	/**
 	 * The number of queries made.
 	 *
 	 * @since 1.2.0
 	 * @var int
 	 */
 	public $num_queries = 0;
 
 	/**
 	 * Count of rows returned by the last query.
 	 *
 	 * @since 0.71
 	 * @var int
 	 */
 	public $num_rows = 0;
 
 	/**
 	 * Count of rows affected by the last query.
 	 *
 	 * @since 0.71
 	 * @var int
 	 */
 	public $rows_affected = 0;
 
 	/**
 	 * The ID generated for an AUTO_INCREMENT column by the last query (usually INSERT).
 	 *
 	 * @since 0.71
 	 * @var int
 	 */
 	public $insert_id = 0;
 
 	/**
 	 * The last query made.
 	 *
 	 * @since 0.71
 	 * @var string
 	 */
 	public $last_query;
 
 	/**
 	 * Results of the last query.
 	 *
 	 * @since 0.71
 	 * @var array|null
 	 */
 	public $last_result;
 
 	/**
 	 * MySQL result, which is either a resource or boolean.
 	 *
 	 * @since 0.71
 	 * @var mixed
 	 */
 	protected $result;
 
 	/**
 	 * Cached column info, for sanity checking data before inserting.
 	 *
 	 * @since 4.2.0
 	 * @var array
 	 */
 	protected $col_meta = array();
 
 	/**
 	 * Calculated character sets on tables.
 	 *
 	 * @since 4.2.0
 	 * @var array
 	 */
 	protected $table_charset = array();
 
 	/**
 	 * Whether text fields in the current query need to be sanity checked. Default false.
 	 *
 	 * @since 4.2.0
 	 * @var bool
 	 */
 	protected $check_current_query = true;
 
 	/**
 	 * Flag to ensure we don't run into recursion problems when checking the collation.
 	 *
 	 * @since 4.2.0
 	 * @see wpdb::check_safe_collation()
 	 * @var bool
 	 */
 	private $checking_collation = false;
 
 	/**
 	 * Saved info on the table column.
 	 *
 	 * @since 0.71
 	 * @var array
 	 */
 	protected $col_info;
 
 	/**
 	 * Log of queries that were executed, for debugging purposes.
 	 *
 	 * @since 1.5.0
 	 * @since 2.5.0 The third element in each query log was added to record the calling functions.
 	 * @since 5.1.0 The fourth element in each query log was added to record the start time.
 	 * @since 5.3.0 The fifth element in each query log was added to record custom data.
 	 *
 	 * @var array[] {
 	 *     Array of queries that were executed.
 	 *
 	 *     @type array ...$0 {
 	 *         Data for each query.
 	 *
 	 *         @type string $0 The query's SQL.
 	 *         @type float  $1 Total time spent on the query, in seconds.
 	 *         @type string $2 Comma-separated list of the calling functions.
 	 *         @type float  $3 Unix timestamp of the time at the start of the query.
 	 *         @type array  $4 Custom query data.
 	 *     }
 	 * }
 	 */
 	public $queries;
 
 	/**
 	 * The number of times to retry reconnecting before dying. Default 5.
 	 *
 	 * @since 3.9.0
 	 * @see wpdb::check_connection()
 	 * @var int
 	 */
 	protected $reconnect_retries = 5;
 
 	/**
 	 * WordPress table prefix
 	 *
 	 * You can set this to have multiple WordPress installations in a single database.
 	 * The second reason is for possible security precautions.
 	 *
 	 * @since 2.5.0
 	 * @var string
 	 */
 	public $prefix = '';
 
 	/**
 	 * WordPress base table prefix.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $base_prefix;
 
 	/**
 	 * Whether the database queries are ready to start executing.
 	 *
 	 * @since 2.3.2
 	 * @var bool
 	 */
 	public $ready = false;
 
 	/**
 	 * Blog ID.
 	 *
 	 * @since 3.0.0
 	 * @var int
 	 */
 	public $blogid = 0;
 
 	/**
 	 * Site ID.
 	 *
 	 * @since 3.0.0
 	 * @var int
 	 */
 	public $siteid = 0;
 
 	/**
 	 * List of WordPress per-blog tables.
 	 *
 	 * @since 2.5.0
 	 * @see wpdb::tables()
 	 * @var array
 	 */
 	public $tables = array(
 		'posts',
 		'comments',
 		'links',
 		'options',
 		'postmeta',
 		'terms',
 		'term_taxonomy',
 		'term_relationships',
 		'termmeta',
 		'commentmeta',
 	);
 
 	/**
 	 * List of deprecated WordPress tables.
 	 *
 	 * 'categories', 'post2cat', and 'link2cat' were deprecated in 2.3.0, db version 5539.
 	 *
 	 * @since 2.9.0
 	 * @see wpdb::tables()
 	 * @var array
 	 */
 	public $old_tables = array( 'categories', 'post2cat', 'link2cat' );
 
 	/**
 	 * List of WordPress global tables.
 	 *
 	 * @since 3.0.0
 	 * @see wpdb::tables()
 	 * @var array
 	 */
 	public $global_tables = array( 'users', 'usermeta' );
 
 	/**
 	 * List of Multisite global tables.
 	 *
 	 * @since 3.0.0
 	 * @see wpdb::tables()
 	 * @var array
 	 */
 	public $ms_global_tables = array(
 		'blogs',
 		'blogmeta',
 		'signups',
 		'site',
 		'sitemeta',
 		'sitecategories',
 		'registration_log',
 	);
 
 	/**
 	 * WordPress Comments table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $comments;
 
 	/**
 	 * WordPress Comment Metadata table.
 	 *
 	 * @since 2.9.0
 	 * @var string
 	 */
 	public $commentmeta;
 
 	/**
 	 * WordPress Links table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $links;
 
 	/**
 	 * WordPress Options table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $options;
 
 	/**
 	 * WordPress Post Metadata table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $postmeta;
 
 	/**
 	 * WordPress Posts table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $posts;
 
 	/**
 	 * WordPress Terms table.
 	 *
 	 * @since 2.3.0
 	 * @var string
 	 */
 	public $terms;
 
 	/**
 	 * WordPress Term Relationships table.
 	 *
 	 * @since 2.3.0
 	 * @var string
 	 */
 	public $term_relationships;
 
 	/**
 	 * WordPress Term Taxonomy table.
 	 *
 	 * @since 2.3.0
 	 * @var string
 	 */
 	public $term_taxonomy;
 
 	/**
 	 * WordPress Term Meta table.
 	 *
 	 * @since 4.4.0
 	 * @var string
 	 */
 	public $termmeta;
 
 	//
 	// Global and Multisite tables
 	//
 
 	/**
 	 * WordPress User Metadata table.
 	 *
 	 * @since 2.3.0
 	 * @var string
 	 */
 	public $usermeta;
 
 	/**
 	 * WordPress Users table.
 	 *
 	 * @since 1.5.0
 	 * @var string
 	 */
 	public $users;
 
 	/**
 	 * Multisite Blogs table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $blogs;
 
 	/**
 	 * Multisite Blog Metadata table.
 	 *
 	 * @since 5.1.0
 	 * @var string
 	 */
 	public $blogmeta;
 
 	/**
 	 * Multisite Registration Log table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $registration_log;
 
 	/**
 	 * Multisite Signups table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $signups;
 
 	/**
 	 * Multisite Sites table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $site;
 
 	/**
 	 * Multisite Sitewide Terms table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $sitecategories;
 
 	/**
 	 * Multisite Site Metadata table.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $sitemeta;
 
 	/**
 	 * Format specifiers for DB columns.
 	 *
 	 * Columns not listed here default to %s. Initialized during WP load.
 	 * Keys are column names, values are format types: 'ID' => '%d'.
 	 *
 	 * @since 2.8.0
 	 * @see wpdb::prepare()
 	 * @see wpdb::insert()
 	 * @see wpdb::update()
 	 * @see wpdb::delete()
 	 * @see wp_set_wpdb_vars()
 	 * @var array
 	 */
 	public $field_types = array();
 
 	/**
 	 * Database table columns charset.
 	 *
 	 * @since 2.2.0
 	 * @var string
 	 */
 	public $charset;
 
 	/**
 	 * Database table columns collate.
 	 *
 	 * @since 2.2.0
 	 * @var string
 	 */
 	public $collate;
 
 	/**
 	 * Database Username.
 	 *
 	 * @since 2.9.0
 	 * @var string
 	 */
 	protected $dbuser;
 
 	/**
 	 * Database Password.
 	 *
 	 * @since 3.1.0
 	 * @var string
 	 */
 	protected $dbpassword;
 
 	/**
 	 * Database Name.
 	 *
 	 * @since 3.1.0
 	 * @var string
 	 */
 	protected $dbname;
 
 	/**
 	 * Database Host.
 	 *
 	 * @since 3.1.0
 	 * @var string
 	 */
 	protected $dbhost;
 
 	/**
 	 * Database Handle.
 	 *
 	 * @since 0.71
 	 * @var string
 	 */
 	protected $dbh;
 
 	/**
 	 * A textual description of the last query/get_row/get_var call.
 	 *
 	 * @since 3.0.0
 	 * @var string
 	 */
 	public $func_call;
 
 	/**
 	 * Whether MySQL is used as the database engine.
 	 *
 	 * Set in wpdb::db_connect() to true, by default. This is used when checking
 	 * against the required MySQL version for WordPress. Normally, a replacement
 	 * database drop-in (db.php) will skip these checks, but setting this to true
 	 * will force the checks to occur.
 	 *
 	 * @since 3.3.0
 	 * @var bool
 	 */
 	public $is_mysql = null;
 
 	/**
 	 * A list of incompatible SQL modes.
 	 *
 	 * @since 3.9.0
 	 * @var array
 	 */
 	protected $incompatible_modes = array(
 		'NO_ZERO_DATE',
 		'ONLY_FULL_GROUP_BY',
 		'STRICT_TRANS_TABLES',
 		'STRICT_ALL_TABLES',
 		'TRADITIONAL',
 		'ANSI',
 	);
 
 	/**
 	 * Whether to use mysqli over mysql. Default false.
 	 *
 	 * @since 3.9.0
 	 * @var bool
 	 */
 	private $use_mysqli = false;
 
 	/**
 	 * Whether we've managed to successfully connect at some point.
 	 *
 	 * @since 3.9.0
 	 * @var bool
 	 */
 	private $has_connected = false;
 
 	/**
 	 * Connects to the database server and selects a database.
 	 *
 	 * PHP5 style constructor for compatibility with PHP5. Does the actual setting up
 	 * of the class properties and connection to the database.
 	 *
 	 * @since 2.0.8
 	 *
 	 * @link https://core.trac.wordpress.org/ticket/3354
 	 * @global string $wp_version The WordPress version string.
 	 *
 	 * @param string $dbuser     MySQL database user.
 	 * @param string $dbpassword MySQL database password.
 	 * @param string $dbname     MySQL database name.
 	 * @param string $dbhost     MySQL database host.
 	 */
 	public function __construct( $dbuser, $dbpassword, $dbname, $dbhost ) {
 		if ( WP_DEBUG && WP_DEBUG_DISPLAY ) {
 			$this->show_errors();
 		}
 
 		// Use ext/mysqli if it exists unless WP_USE_EXT_MYSQL is defined as true.
 		if ( function_exists( 'mysqli_connect' ) ) {
 			$this->use_mysqli = true;
 
 			if ( defined( 'WP_USE_EXT_MYSQL' ) ) {
 				$this->use_mysqli = ! WP_USE_EXT_MYSQL;
 			}
 		}
 
 		$this->dbuser     = $dbuser;
 		$this->dbpassword = $dbpassword;
 		$this->dbname     = $dbname;
 		$this->dbhost     = $dbhost;
 
 		// wp-config.php creation will manually connect when ready.
 		if ( defined( 'WP_SETUP_CONFIG' ) ) {
 			return;
 		}
 
 		$this->db_connect();
 	}
 
 	/**
 	 * Makes private properties readable for backward compatibility.
 	 *
 	 * @since 3.5.0
 	 *
 	 * @param string $name The private member to get, and optionally process.
 	 * @return mixed The private member.
 	 */
 	public function __get( $name ) {
 		if ( 'col_info' === $name ) {
 			$this->load_col_info();
 		}
 
 		return $this->$name;
 	}
 
 	/**
 	 * Makes private properties settable for backward compatibility.
 	 *
 	 * @since 3.5.0
 	 *
 	 * @param string $name  The private member to set.
 	 * @param mixed  $value The value to set.
 	 */
 	public function __set( $name, $value ) {
 		$protected_members = array(
 			'col_meta',
 			'table_charset',
 			'check_current_query',
 		);
 		if ( in_array( $name, $protected_members, true ) ) {
 			return;
 		}
 		$this->$name = $value;
 	}
 
 	/**
 	 * Makes private properties check-able for backward compatibility.
 	 *
 	 * @since 3.5.0
 	 *
 	 * @param string $name The private member to check.
 	 * @return bool If the member is set or not.
 	 */
 	public function __isset( $name ) {
 		return isset( $this->$name );
 	}
 
 	/**
 	 * Makes private properties un-settable for backward compatibility.
 	 *
 	 * @since 3.5.0
 	 *
 	 * @param string $name  The private member to unset
 	 */
 	public function __unset( $name ) {
 		unset( $this->$name );
 	}
 
 	/**
 	 * Sets $this->charset and $this->collate.
 	 *
 	 * @since 3.1.0
 	 */
 	public function init_charset() {
 		$charset = '';
 		$collate = '';
 
 		if ( function_exists( 'is_multisite' ) && is_multisite() ) {
 			$charset = 'utf8';
 			if ( defined( 'DB_COLLATE' ) && DB_COLLATE ) {
 				$collate = DB_COLLATE;
 			} else {
 				$collate = 'utf8_general_ci';
 			}
 		} elseif ( defined( 'DB_COLLATE' ) ) {
 			$collate = DB_COLLATE;
 		}
 
 		if ( defined( 'DB_CHARSET' ) ) {
 			$charset = DB_CHARSET;
 		}
 
 		$charset_collate = $this->determine_charset( $charset, $collate );
 
 		$this->charset = $charset_collate['charset'];
 		$this->collate = $charset_collate['collate'];
 	}
 
 	/**
 	 * Determines the best charset and collation to use given a charset and collation.
 	 *
 	 * For example, when able, utf8mb4 should be used instead of utf8.
 	 *
 	 * @since 4.6.0
 	 *
 	 * @param string $charset The character set to check.
 	 * @param string $collate The collation to check.
 	 * @return array {
 	 *     The most appropriate character set and collation to use.
 	 *
 	 *     @type string $charset Character set.
 	 *     @type string $collate Collation.
 	 * }
 	 */
 	public function determine_charset( $charset, $collate ) {
 		if ( ( $this->use_mysqli && ! ( $this->dbh instanceof mysqli ) ) || empty( $this->dbh ) ) {
 			return compact( 'charset', 'collate' );
 		}
 
 		if ( 'utf8' === $charset && $this->has_cap( 'utf8mb4' ) ) {
 			$charset = 'utf8mb4';
 		}
 
 		if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
 			$charset = 'utf8';
 			$collate = str_replace( 'utf8mb4_', 'utf8_', $collate );
 		}
 
 		if ( 'utf8mb4' === $charset ) {
 			// _general_ is outdated, so we can upgrade it to _unicode_, instead.
 			if ( ! $collate || 'utf8_general_ci' === $collate ) {
 				$collate = 'utf8mb4_unicode_ci';
 			} else {
 				$collate = str_replace( 'utf8_', 'utf8mb4_', $collate );
 			}
 		}
 
 		// _unicode_520_ is a better collation, we should use that when it's available.
 		if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) {
 			$collate = 'utf8mb4_unicode_520_ci';
 		}
 
 		return compact( 'charset', 'collate' );
 	}
 
 	/**
 	 * Sets the connection's character set.
 	 *
 	 * @since 3.1.0
 	 *
 	 * @param resource $dbh     The resource given by mysql_connect.
 	 * @param string   $charset Optional. The character set. Default null.
 	 * @param string   $collate Optional. The collation. Default null.
 	 */
 	public function set_charset( $dbh, $charset = null, $collate = null ) {
 		if ( ! isset( $charset ) ) {
 			$charset = $this->charset;
 		}
 		if ( ! isset( $collate ) ) {
 			$collate = $this->collate;
 		}
 		if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
 			$set_charset_succeeded = true;
 
 			if ( $this->use_mysqli ) {
 				if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
 					$set_charset_succeeded = mysqli_set_charset( $dbh, $charset );
 				}
 
 				if ( $set_charset_succeeded ) {
 					$query = $this->prepare( 'SET NAMES %s', $charset );
 					if ( ! empty( $collate ) ) {
 						$query .= $this->prepare( ' COLLATE %s', $collate );
 					}
 					mysqli_query( $dbh, $query );
 				}
 			} else {
 				if ( function_exists( 'mysql_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
 					$set_charset_succeeded = mysql_set_charset( $charset, $dbh );
 				}
 				if ( $set_charset_succeeded ) {
 					$query = $this->prepare( 'SET NAMES %s', $charset );
 					if ( ! empty( $collate ) ) {
 						$query .= $this->prepare( ' COLLATE %s', $collate );
 					}
 					mysql_query( $query, $dbh );
 				}
 			}
 		}
 	}
 
 	/**
 	 * Changes the current SQL mode, and ensures its WordPress compatibility.
 	 *
 	 * If no modes are passed, it will ensure the current MySQL server modes are compatible.
 	 *
 	 * @since 3.9.0
 	 *
 	 * @param array $modes Optional. A list of SQL modes to set. Default empty array.
 	 */
 	public function set_sql_mode( $modes = array() ) {
 		if ( empty( $modes ) ) {
 			if ( $this->use_mysqli ) {
 				$res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
 			} else {
 				$res = mysql_query( 'SELECT @@SESSION.sql_mode', $this->dbh );
 			}
 
 			if ( empty( $res ) ) {
 				return;
 			}
 
 			if ( $this->use_mysqli ) {
 				$modes_array = mysqli_fetch_array( $res );
 				if ( empty( $modes_array[0] ) ) {
 					return;
 				}
 				$modes_str = $modes_array[0];
 			} else {
 				$modes_str = mysql_result( $res, 0 );
 			}
 
 			if ( empty( $modes_str ) ) {
 				return;
 			}
 
 			$modes = explode( ',', $modes_str );
 		}
 
 		$modes = array_change_key_case( $modes, CASE_UPPER );
 
 		/**
 		 * Filters the list of incompatible SQL modes to exclude.
 		 *
 		 * @since 3.9.0
 		 *
 		 * @param array $incompatible_modes An array of incompatible modes.
 		 */
 		$incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
 
 		foreach ( $modes as $i => $mode ) {
 			if ( in_array( $mode, $incompatible_modes, true ) ) {
 				unset( $modes[ $i ] );
 			}
 		}
 
 		$modes_str = implode( ',', $modes );
 
 		if ( $this->use_mysqli ) {
 			mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
 		} else {
 			mysql_query( "SET SESSION sql_mode='$modes_str'", $this->dbh );
 		}
 	}
 
 	/**
 	 * Sets the table prefix for the WordPress tables.
 	 *
 	 * @since 2.5.0
 	 *
 	 * @param string $prefix          Alphanumeric name for the new prefix.
 	 * @param bool   $set_table_names Optional. Whether the table names, e.g. wpdb::$posts,
 	 *                                should be updated or not. Default true.
 	 * @return string|WP_Error Old prefix or WP_Error on error.
 	 */
 	public function set_prefix( $prefix, $set_table_names = true ) {
 
 		if ( preg_match( '|[^a-z0-9_]|i', $prefix ) ) {
 			return new WP_Error( 'invalid_db_prefix', 'Invalid database prefix' );
 		}
 
 		$old_prefix = is_multisite() ? '' : $prefix;
 
 		if ( isset( $this->base_prefix ) ) {
 			$old_prefix = $this->base_prefix;
 		}
 
 		$this->base_prefix = $prefix;
 
 		if ( $set_table_names ) {
 			foreach ( $this->tables( 'global' ) as $table => $prefixed_table ) {
 				$this->$table = $prefixed_table;
 			}
 
 			if ( is_multisite() && empty( $this->blogid ) ) {
 				return $old_prefix;
 			}
 
 			$this->prefix = $this->get_blog_prefix();
 
 			foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
 				$this->$table = $prefixed_table;
 			}
 
 			foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
 				$this->$table = $prefixed_table;
 			}
 		}
 		return $old_prefix;
 	}
 
 	/**
 	 * Sets blog ID.
 	 *
 	 * @since 3.0.0
 	 *
 	 * @param int $blog_id
 	 * @param int $network_id Optional.
 	 * @return int Previous blog ID.
 	 */
 	public function set_blog_id( $blog_id, $network_id = 0 ) {
 		if ( ! empty( $network_id ) ) {
 			$this->siteid = $network_id;
 		}
 
 		$old_blog_id  = $this->blogid;
 		$this->blogid = $blog_id;
 
 		$this->prefix = $this->get_blog_prefix();
 
 		foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
 			$this->$table = $prefixed_table;
 		}
 
 		foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
 			$this->$table = $prefixed_table;
 		}
 
 		return $old_blog_id;
 	}
 
 	/**
 	 * Gets blog prefix.
 	 *
 	 * @since 3.0.0
 	 *
 	 * @param int $blog_id Optional.
 	 * @return string Blog prefix.
 	 */
 	public function get_blog_prefix( $blog_id = null ) {
 		if ( is_multisite() ) {
 			if ( null === $blog_id ) {
 				$blog_id = $this->blogid;
 			}
 
 			$blog_id = (int) $blog_id;
 
 			if ( defined( 'MULTISITE' ) && ( 0 === $blog_id || 1 === $blog_id ) ) {
 				return $this->base_prefix;
 			} else {
 				return $this->base_prefix . $blog_id . '_';
 			}
 		} else {
 			return $this->base_prefix;
 		}
 	}
 
 	/**
 	 * Returns an array of WordPress tables.
 	 *
 	 * Also allows for the CUSTOM_USER_TABLE and CUSTOM_USER_META_TABLE to override the WordPress users
 	 * and usermeta tables that would otherwise be determined by the prefix.
 	 *
 	 * The $scope argument can take one of the following:
 	 *
 	 * 'all' - returns 'all' and 'global' tables. No old tables are returned.
 	 * 'blog' - returns the blog-level tables for the queried blog.
 	 * 'global' - returns the global tables for the installation, returning multisite tables only on multisite.
 	 * 'ms_global' - returns the multisite global tables, regardless if current installation is multisite.
 	 * 'old' - returns tables which are deprecated.
 	 *
 	 * @since 3.0.0
 	 *
 	 * @uses wpdb::$tables
 	 * @uses wpdb::$old_tables
 	 * @uses wpdb::$global_tables
 	 * @uses wpdb::$ms_global_tables
 	 *
 	 * @param string $scope   Optional. Possible values include 'all', 'global', 'ms_global', 'blog',
 	 *                        or 'old' tables. Default 'all'.
 	 * @param bool   $prefix  Optional. Whether to include table prefixes. If blog prefix is requested,
 	 *                        then the custom users and usermeta tables will be mapped. Default true.
 	 * @param int    $blog_id Optional. The blog_id to prefix. Used only when prefix is requested.
 	 *                        Defaults to wpdb::$blogid.
 	 * @return array Table names. When a prefix is requested, the key is the unprefixed table name.
 	 */
 	public function tables( $scope = 'all', $prefix = true, $blog_id = 0 ) {
 		switch ( $scope ) {
 			case 'all':
 				$tables = array_merge( $this->global_tables, $this->tables );
 				if ( is_multisite() ) {
 					$tables = array_merge( $tables, $this->ms_global_tables );
 				}
 				break;
 			case 'blog':
 				$tables = $this->tables;
 				break;
 			case 'global':
 				$tables = $this->global_tables;
 				if ( is_multisite() ) {
 					$tables = array_merge( $tables, $this->ms_global_tables );
 				}
 				break;
 			case 'ms_global':
 				$tables = $this->ms_global_tables;
 				break;
 			case 'old':
 				$tables = $this->old_tables;
 				break;
 			default:
 				return array();
 		}
 
 		if ( $prefix ) {
 			if ( ! $blog_id ) {
 				$blog_id = $this->blogid;
 			}
 			$blog_prefix   = $this->get_blog_prefix( $blog_id );
 			$base_prefix   = $this->base_prefix;
 			$global_tables = array_merge( $this->global_tables, $this->ms_global_tables );
 			foreach ( $tables as $k => $table ) {
 				if ( in_array( $table, $global_tables, true ) ) {
 					$tables[ $table ] = $base_prefix . $table;
 				} else {
 					$tables[ $table ] = $blog_prefix . $table;
 				}
 				unset( $tables[ $k ] );
 			}
 
 			if ( isset( $tables['users'] ) && defined( 'CUSTOM_USER_TABLE' ) ) {
 				$tables['users'] = CUSTOM_USER_TABLE;
 			}
 
 			if ( isset( $tables['usermeta'] ) && defined( 'CUSTOM_USER_META_TABLE' ) ) {
 				$tables['usermeta'] = CUSTOM_USER_META_TABLE;
 			}
 		}
 
 		return $tables;
 	}
 
 	/**
 	 * Selects a database using the current database connection.
 	 *
 	 * The database name will be changed based on the current database connection.
 	 * On failure, the execution will bail and display a DB error.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string        $db  MySQL database name.
 	 * @param resource|null $dbh Optional link identifier.
 	 */
 	public function select( $db, $dbh = null ) {
 		if ( is_null( $dbh ) ) {
 			$dbh = $this->dbh;
 		}
 
 		if ( $this->use_mysqli ) {
 			$success = mysqli_select_db( $dbh, $db );
 		} else {
 			$success = mysql_select_db( $db, $dbh );
 		}
 		if ( ! $success ) {
 			$this->ready = false;
 			if ( ! did_action( 'template_redirect' ) ) {
 				wp_load_translations_early();
 
 				$message = '<h1>' . __( 'Can&#8217;t select database' ) . "</h1>\n";
 
 				$message .= '<p>' . sprintf(
 					/* translators: %s: Database name. */
 					__( 'We were able to connect to the database server (which means your username and password is okay) but not able to select the %s database.' ),
 					'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
 				) . "</p>\n";
 
 				$message .= "<ul>\n";
 				$message .= '<li>' . __( 'Are you sure it exists?' ) . "</li>\n";
 
 				$message .= '<li>' . sprintf(
 					/* translators: 1: Database user, 2: Database name. */
 					__( 'Does the user %1$s have permission to use the %2$s database?' ),
 					'<code>' . htmlspecialchars( $this->dbuser, ENT_QUOTES ) . '</code>',
 					'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
 				) . "</li>\n";
 
 				$message .= '<li>' . sprintf(
 					/* translators: %s: Database name. */
 					__( 'On some systems the name of your database is prefixed with your username, so it would be like <code>username_%1$s</code>. Could that be the problem?' ),
 					htmlspecialchars( $db, ENT_QUOTES )
 				) . "</li>\n";
 
 				$message .= "</ul>\n";
 
 				$message .= '<p>' . sprintf(
 					/* translators: %s: Support forums URL. */
 					__( 'If you don&#8217;t know how to set up a database you should <strong>contact your host</strong>. If all else fails you may find help at the <a href="%s">WordPress Support Forums</a>.' ),
 					__( 'https://wordpress.org/support/forums/' )
 				) . "</p>\n";
 
 				$this->bail( $message, 'db_select_fail' );
 			}
 		}
 	}
 
 	/**
 	 * Do not use, deprecated.
 	 *
 	 * Use esc_sql() or wpdb::prepare() instead.
 	 *
 	 * @since 2.8.0
 	 * @deprecated 3.6.0 Use wpdb::prepare()
 	 * @see wpdb::prepare()
 	 * @see esc_sql()
 	 *
 	 * @param string $string
 	 * @return string
 	 */
 	function _weak_escape( $string ) {
 		if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
 			_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
 		}
 		return addslashes( $string );
 	}
 
 	/**
 	 * Real escape, using mysqli_real_escape_string() or mysql_real_escape_string().
 	 *
 	 * @since 2.8.0
 	 *
 	 * @see mysqli_real_escape_string()
 	 * @see mysql_real_escape_string()
 	 *
 	 * @param string $string String to escape.
 	 * @return string Escaped string.
 	 */
 	function _real_escape( $string ) {
 		if ( ! is_scalar( $string ) && ! is_null( $string ) ) {
 			return '';
 		}
 
 		if ( $this->dbh ) {
 			if ( $this->use_mysqli ) {
 				$escaped = mysqli_real_escape_string( $this->dbh, $string );
 			} else {
 				$escaped = mysql_real_escape_string( $string, $this->dbh );
 			}
 		} else {
 			$class = get_class( $this );
 			if ( function_exists( '__' ) ) {
 				/* translators: %s: Database access abstraction class, usually wpdb or a class extending wpdb. */
 				_doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
 			} else {
 				_doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
 			}
 			$escaped = addslashes( $string );
 		}
 
 		return $this->add_placeholder_escape( $escaped );
 	}
 
 	/**
 	 * Escapes data. Works on arrays.
 	 *
 	 * @since 2.8.0
 	 *
 	 * @uses wpdb::_real_escape()
 	 *
 	 * @param string|array $data Data to escape.
 	 * @return string|array Escaped data, in the same type as supplied.
 	 */
 	public function _escape( $data ) {
 		if ( is_array( $data ) ) {
 			foreach ( $data as $k => $v ) {
 				if ( is_array( $v ) ) {
 					$data[ $k ] = $this->_escape( $v );
 				} else {
 					$data[ $k ] = $this->_real_escape( $v );
 				}
 			}
 		} else {
 			$data = $this->_real_escape( $data );
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Do not use, deprecated.
 	 *
 	 * Use esc_sql() or wpdb::prepare() instead.
 	 *
 	 * @since 0.71
 	 * @deprecated 3.6.0 Use wpdb::prepare()
 	 * @see wpdb::prepare()
 	 * @see esc_sql()
 	 *
 	 * @param string|array $data Data to escape.
 	 * @return string|array Escaped data, in the same type as supplied.
 	 */
 	public function escape( $data ) {
 		if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
 			_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
 		}
 		if ( is_array( $data ) ) {
 			foreach ( $data as $k => $v ) {
 				if ( is_array( $v ) ) {
 					$data[ $k ] = $this->escape( $v, 'recursive' );
 				} else {
 					$data[ $k ] = $this->_weak_escape( $v, 'internal' );
 				}
 			}
 		} else {
 			$data = $this->_weak_escape( $data, 'internal' );
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Escapes content by reference for insertion into the database, for security.
 	 *
 	 * @uses wpdb::_real_escape()
 	 *
 	 * @since 2.3.0
 	 *
 	 * @param string $string String to escape.
 	 */
 	public function escape_by_ref( &$string ) {
 		if ( ! is_float( $string ) ) {
 			$string = $this->_real_escape( $string );
 		}
 	}
 
 	/**
 	 * Prepares a SQL query for safe execution.
 	 *
 	 * Uses sprintf()-like syntax. The following placeholders can be used in the query string:
 	 *   %d (integer)
 	 *   %f (float)
 	 *   %s (string)
 	 *
 	 * All placeholders MUST be left unquoted in the query string. A corresponding argument
 	 * MUST be passed for each placeholder.
 	 *
 	 * Note: There is one exception to the above: for compatibility with old behavior,
 	 * numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes
 	 * added by this function, so should be passed with appropriate quotes around them.
 	 *
 	 * Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards
 	 * (for example, to use in LIKE syntax) must be passed via a substitution argument containing
 	 * the complete LIKE string, these cannot be inserted directly in the query string.
 	 * Also see wpdb::esc_like().
 	 *
 	 * Arguments may be passed as individual arguments to the method, or as a single array
 	 * containing all arguments. A combination of the two is not supported.
 	 *
 	 * Examples:
 	 *     $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s", array( 'foo', 1337, '%bar' ) );
 	 *     $wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
 	 *
 	 * @since 2.3.0
 	 * @since 5.3.0 Formalized the existing and already documented `...$args` parameter
 	 *              by updating the function signature. The second parameter was changed
 	 *              from `$args` to `...$args`.
 	 *
 	 * @link https://www.php.net/sprintf Description of syntax.
 	 *
 	 * @param string      $query   Query statement with sprintf()-like placeholders.
 	 * @param array|mixed $args    The array of variables to substitute into the query's placeholders
 	 *                             if being called with an array of arguments, or the first variable
 	 *                             to substitute into the query's placeholders if being called with
 	 *                             individual arguments.
 	 * @param mixed       ...$args Further variables to substitute into the query's placeholders
 	 *                             if being called with individual arguments.
 	 * @return string|void Sanitized query string, if there is a query to prepare.
 	 */
 	public function prepare( $query, ...$args ) {
 		if ( is_null( $query ) ) {
 			return;
 		}
 
 		// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
 		if ( strpos( $query, '%' ) === false ) {
 			wp_load_translations_early();
 			_doing_it_wrong(
 				'wpdb::prepare',
 				sprintf(
 					/* translators: %s: wpdb::prepare() */
 					__( 'The query argument of %s must have a placeholder.' ),
 					'wpdb::prepare()'
 				),
 				'3.9.0'
 			);
 		}
 
 		// If args were passed as an array (as in vsprintf), move them up.
 		$passed_as_array = false;
 		if ( is_array( $args[0] ) && count( $args ) === 1 ) {
 			$passed_as_array = true;
 			$args            = $args[0];
 		}
 
 		foreach ( $args as $arg ) {
 			if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
 				wp_load_translations_early();
 				_doing_it_wrong(
 					'wpdb::prepare',
 					sprintf(
 						/* translators: %s: Value type. */
 						__( 'Unsupported value type (%s).' ),
 						gettype( $arg )
 					),
 					'4.8.2'
 				);
 			}
 		}
 
 		/*
 		 * Specify the formatting allowed in a placeholder. The following are allowed:
 		 *
 		 * - Sign specifier. eg, $+d
 		 * - Numbered placeholders. eg, %1$s
 		 * - Padding specifier, including custom padding characters. eg, %05s, %'#5s
 		 * - Alignment specifier. eg, %05-s
 		 * - Precision specifier. eg, %.2f
 		 */
 		$allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
 
 		/*
 		 * If a %s placeholder already has quotes around it, removing the existing quotes and re-inserting them
 		 * ensures the quotes are consistent.
 		 *
 		 * For backward compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
 		 * used in the middle of longer strings, or as table name placeholders.
 		 */
 		$query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
 		$query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
 		$query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.
 
 		$query = preg_replace( "/(?<!%)(%($allowed_format)?f)/", '%\\2F', $query ); // Force floats to be locale-unaware.
 
 		$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
 
 		// Count the number of valid placeholders in the query.
 		$placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
 
 		$args_count = count( $args );
 
 		if ( $args_count !== $placeholders ) {
 			if ( 1 === $placeholders && $passed_as_array ) {
 				// If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
 				wp_load_translations_early();
 				_doing_it_wrong(
 					'wpdb::prepare',
 					__( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ),
 					'4.9.0'
 				);
 
 				return;
 			} else {
 				/*
 				 * If we don't have the right number of placeholders, but they were passed as individual arguments,
 				 * or we were expecting multiple arguments in an array, throw a warning.
 				 */
 				wp_load_translations_early();
 				_doing_it_wrong(
 					'wpdb::prepare',
 					sprintf(
 						/* translators: 1: Number of placeholders, 2: Number of arguments passed. */
 						__( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
 						$placeholders,
 						$args_count
 					),
 					'4.8.3'
 				);
 
 				/*
 				 * If we don't have enough arguments to match the placeholders,
 				 * return an empty string to avoid a fatal error on PHP 8.
 				 */
 				if ( $args_count < $placeholders ) {
 					$max_numbered_placeholder = ! empty( $matches[3] ) ? max( array_map( 'intval', $matches[3] ) ) : 0;
 
 					if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
 						return '';
 					}
 				}
 			}
 		}
 
 		array_walk( $args, array( $this, 'escape_by_ref' ) );
 		$query = vsprintf( $query, $args );
 
 		return $this->add_placeholder_escape( $query );
 	}
 
 	/**
 	 * First half of escaping for LIKE special characters % and _ before preparing for MySQL.
 	 *
 	 * Use this only before wpdb::prepare() or esc_sql(). Reversing the order is very bad for security.
 	 *
 	 * Example Prepared Statement:
 	 *
 	 *     $wild = '%';
 	 *     $find = 'only 43% of planets';
 	 *     $like = $wild . $wpdb->esc_like( $find ) . $wild;
 	 *     $sql  = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_content LIKE %s", $like );
 	 *
 	 * Example Escape Chain:
 	 *
 	 *     $sql  = esc_sql( $wpdb->esc_like( $input ) );
 	 *
 	 * @since 4.0.0
 	 *
 	 * @param string $text The raw text to be escaped. The input typed by the user
 	 *                     should have no extra or deleted slashes.
 	 * @return string Text in the form of a LIKE phrase. The output is not SQL safe.
 	 *                Call wpdb::prepare() or wpdb::_real_escape() next.
 	 */
 	public function esc_like( $text ) {
 		return addcslashes( $text, '_%\\' );
 	}
 
 	/**
 	 * Prints SQL/DB error.
 	 *
 	 * @since 0.71
 	 *
 	 * @global array $EZSQL_ERROR Stores error information of query and error string.
 	 *
 	 * @param string $str The error to display.
 	 * @return void|false Void if the showing of errors is enabled, false if disabled.
 	 */
 	public function print_error( $str = '' ) {
 		global $EZSQL_ERROR;
 
 		if ( ! $str ) {
 			if ( $this->use_mysqli ) {
 				$str = mysqli_error( $this->dbh );
 			} else {
 				$str = mysql_error( $this->dbh );
 			}
 		}
 		$EZSQL_ERROR[] = array(
 			'query'     => $this->last_query,
 			'error_str' => $str,
 		);
 
 		if ( $this->suppress_errors ) {
 			return false;
 		}
 
 		wp_load_translations_early();
 
 		$caller = $this->get_caller();
 		if ( $caller ) {
 			/* translators: 1: Database error message, 2: SQL query, 3: Name of the calling function. */
 			$error_str = sprintf( __( 'WordPress database error %1$s for query %2$s made by %3$s' ), $str, $this->last_query, $caller );
 		} else {
 			/* translators: 1: Database error message, 2: SQL query. */
 			$error_str = sprintf( __( 'WordPress database error %1$s for query %2$s' ), $str, $this->last_query );
 		}
 
 		error_log( $error_str );
 
 		// Are we showing errors?
 		if ( ! $this->show_errors ) {
 			return false;
 		}
 
 		// If there is an error then take note of it.
 		if ( is_multisite() ) {
 			$msg = sprintf(
 				"%s [%s]\n%s\n",
 				__( 'WordPress database error:' ),
 				$str,
 				$this->last_query
 			);
 
 			if ( defined( 'ERRORLOGFILE' ) ) {
 				error_log( $msg, 3, ERRORLOGFILE );
 			}
 			if ( defined( 'DIEONDBERROR' ) ) {
 				wp_die( $msg );
 			}
 		} else {
 			$str   = htmlspecialchars( $str, ENT_QUOTES );
 			$query = htmlspecialchars( $this->last_query, ENT_QUOTES );
 
 			printf(
 				'<div id="error"><p class="wpdberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
 				__( 'WordPress database error:' ),
 				$str,
 				$query
 			);
 		}
 	}
 
 	/**
 	 * Enables showing of database errors.
 	 *
 	 * This function should be used only to enable showing of errors.
 	 * wpdb::hide_errors() should be used instead for hiding errors.
 	 *
 	 * @since 0.71
 	 *
 	 * @see wpdb::hide_errors()
 	 *
 	 * @param bool $show Optional. Whether to show errors. Default true.
 	 * @return bool Whether showing of errors was previously active.
 	 */
 	public function show_errors( $show = true ) {
 		$errors            = $this->show_errors;
 		$this->show_errors = $show;
 		return $errors;
 	}
 
 	/**
 	 * Disables showing of database errors.
 	 *
 	 * By default database errors are not shown.
 	 *
 	 * @since 0.71
 	 *
 	 * @see wpdb::show_errors()
 	 *
 	 * @return bool Whether showing of errors was previously active.
 	 */
 	public function hide_errors() {
 		$show              = $this->show_errors;
 		$this->show_errors = false;
 		return $show;
 	}
 
 	/**
 	 * Enables or disables suppressing of database errors.
 	 *
 	 * By default database errors are suppressed.
 	 *
 	 * @since 2.5.0
 	 *
 	 * @see wpdb::hide_errors()
 	 *
 	 * @param bool $suppress Optional. Whether to suppress errors. Default true.
 	 * @return bool Whether suppressing of errors was previously active.
 	 */
 	public function suppress_errors( $suppress = true ) {
 		$errors                = $this->suppress_errors;
 		$this->suppress_errors = (bool) $suppress;
 		return $errors;
 	}
 
 	/**
 	 * Kills cached query results.
 	 *
 	 * @since 0.71
 	 */
 	public function flush() {
 		$this->last_result   = array();
 		$this->col_info      = null;
 		$this->last_query    = null;
 		$this->rows_affected = 0;
 		$this->num_rows      = 0;
 		$this->last_error    = '';
 
 		if ( $this->use_mysqli && $this->result instanceof mysqli_result ) {
 			mysqli_free_result( $this->result );
 			$this->result = null;
 
 			// Sanity check before using the handle.
 			if ( empty( $this->dbh ) || ! ( $this->dbh instanceof mysqli ) ) {
 				return;
 			}
 
 			// Clear out any results from a multi-query.
 			while ( mysqli_more_results( $this->dbh ) ) {
 				mysqli_next_result( $this->dbh );
 			}
 		} elseif ( is_resource( $this->result ) ) {
 			mysql_free_result( $this->result );
 		}
 	}
 
 	/**
 	 * Connects to and selects database.
 	 *
 	 * If $allow_bail is false, the lack of database connection will need to be handled manually.
 	 *
 	 * @since 3.0.0
 	 * @since 3.9.0 $allow_bail parameter added.
 	 *
 	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
 	 * @return bool True with a successful connection, false on failure.
 	 */
 	public function db_connect( $allow_bail = true ) {
 		$this->is_mysql = true;
 
 		/*
 		 * Deprecated in 3.9+ when using MySQLi. No equivalent
 		 * $new_link parameter exists for mysqli_* functions.
 		 */
 		$new_link     = defined( 'MYSQL_NEW_LINK' ) ? MYSQL_NEW_LINK : true;
 		$client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
 
 		if ( $this->use_mysqli ) {
 			$this->dbh = mysqli_init();
 
 			$host    = $this->dbhost;
 			$port    = null;
 			$socket  = null;
 			$is_ipv6 = false;
 
 			$host_data = $this->parse_db_host( $this->dbhost );
 			if ( $host_data ) {
 				list( $host, $port, $socket, $is_ipv6 ) = $host_data;
 			}
 
 			/*
 			 * If using the `mysqlnd` library, the IPv6 address needs to be enclosed
 			 * in square brackets, whereas it doesn't while using the `libmysqlclient` library.
 			 * @see https://bugs.php.net/bug.php?id=67563
 			 */
 			if ( $is_ipv6 && extension_loaded( 'mysqlnd' ) ) {
 				$host = "[$host]";
 			}
 
 			if ( WP_DEBUG ) {
 				mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
 			} else {
 				// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
 				@mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
 			}
 
 			if ( $this->dbh->connect_errno ) {
 				$this->dbh = null;
 
 				/*
 				 * It's possible ext/mysqli is misconfigured. Fall back to ext/mysql if:
 				 *  - We haven't previously connected, and
 				 *  - WP_USE_EXT_MYSQL isn't set to false, and
 				 *  - ext/mysql is loaded.
 				 */
 				$attempt_fallback = true;
 
 				if ( $this->has_connected ) {
 					$attempt_fallback = false;
 				} elseif ( defined( 'WP_USE_EXT_MYSQL' ) && ! WP_USE_EXT_MYSQL ) {
 					$attempt_fallback = false;
 				} elseif ( ! function_exists( 'mysql_connect' ) ) {
 					$attempt_fallback = false;
 				}
 
 				if ( $attempt_fallback ) {
 					$this->use_mysqli = false;
 					return $this->db_connect( $allow_bail );
 				}
 			}
 		} else {
 			if ( WP_DEBUG ) {
 				$this->dbh = mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
 			} else {
 				// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
 				$this->dbh = @mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
 			}
 		}
 
 		if ( ! $this->dbh && $allow_bail ) {
 			wp_load_translations_early();
 
 			// Load custom DB error template, if present.
 			if ( file_exists( WP_CONTENT_DIR . '/db-error.php' ) ) {
 				require_once WP_CONTENT_DIR . '/db-error.php';
 				die();
 			}
 
 			$message = '<h1>' . __( 'Error establishing a database connection' ) . "</h1>\n";
 
 			$message .= '<p>' . sprintf(
 				/* translators: 1: wp-config.php, 2: Database host. */
 				__( 'This either means that the username and password information in your %1$s file is incorrect or we can&#8217;t contact the database server at %2$s. This could mean your host&#8217;s database server is down.' ),
 				'<code>wp-config.php</code>',
 				'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
 			) . "</p>\n";
 
 			$message .= "<ul>\n";
 			$message .= '<li>' . __( 'Are you sure you have the correct username and password?' ) . "</li>\n";
 			$message .= '<li>' . __( 'Are you sure you have typed the correct hostname?' ) . "</li>\n";
 			$message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
 			$message .= "</ul>\n";
 
 			$message .= '<p>' . sprintf(
 				/* translators: %s: Support forums URL. */
 				__( 'If you&#8217;re unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress Support Forums</a>.' ),
 				__( 'https://wordpress.org/support/forums/' )
 			) . "</p>\n";
 
 			$this->bail( $message, 'db_connect_fail' );
 
 			return false;
 		} elseif ( $this->dbh ) {
 			if ( ! $this->has_connected ) {
 				$this->init_charset();
 			}
 
 			$this->has_connected = true;
 
 			$this->set_charset( $this->dbh );
 
 			$this->ready = true;
 			$this->set_sql_mode();
 			$this->select( $this->dbname, $this->dbh );
 
 			return true;
 		}
 
 		return false;
 	}
 
 	/**
 	 * Parses the DB_HOST setting to interpret it for mysqli_real_connect().
 	 *
 	 * mysqli_real_connect() doesn't support the host param including a port or socket
 	 * like mysql_connect() does. This duplicates how mysql_connect() detects a port
 	 * and/or socket file.
 	 *
 	 * @since 4.9.0
 	 *
 	 * @param string $host The DB_HOST setting to parse.
 	 * @return array|false Array containing the host, the port, the socket and
 	 *                     whether it is an IPv6 address, in that order.
 	 *                     False if $host couldn't be parsed.
 	 */
 	public function parse_db_host( $host ) {
 		$port    = null;
 		$socket  = null;
 		$is_ipv6 = false;
 
 		// First peel off the socket parameter from the right, if it exists.
 		$socket_pos = strpos( $host, ':/' );
 		if ( false !== $socket_pos ) {
 			$socket = substr( $host, $socket_pos + 1 );
 			$host   = substr( $host, 0, $socket_pos );
 		}
 
 		// We need to check for an IPv6 address first.
 		// An IPv6 address will always contain at least two colons.
 		if ( substr_count( $host, ':' ) > 1 ) {
 			$pattern = '#^(?:\[)?(?P<host>[0-9a-fA-F:]+)(?:\]:(?P<port>[\d]+))?#';
 			$is_ipv6 = true;
 		} else {
 			// We seem to be dealing with an IPv4 address.
 			$pattern = '#^(?P<host>[^:/]*)(?::(?P<port>[\d]+))?#';
 		}
 
 		$matches = array();
 		$result  = preg_match( $pattern, $host, $matches );
 
 		if ( 1 !== $result ) {
 			// Couldn't parse the address, bail.
 			return false;
 		}
 
 		$host = '';
 		foreach ( array( 'host', 'port' ) as $component ) {
 			if ( ! empty( $matches[ $component ] ) ) {
 				$$component = $matches[ $component ];
 			}
 		}
 
 		return array( $host, $port, $socket, $is_ipv6 );
 	}
 
 	/**
 	 * Checks that the connection to the database is still up. If not, try to reconnect.
 	 *
 	 * If this function is unable to reconnect, it will forcibly die, or if called
 	 * after the {@see 'template_redirect'} hook has been fired, return false instead.
 	 *
 	 * If $allow_bail is false, the lack of database connection will need to be handled manually.
 	 *
 	 * @since 3.9.0
 	 *
 	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
 	 * @return bool|void True if the connection is up.
 	 */
 	public function check_connection( $allow_bail = true ) {
 		if ( $this->use_mysqli ) {
 			if ( ! empty( $this->dbh ) && mysqli_ping( $this->dbh ) ) {
 				return true;
 			}
 		} else {
 			if ( ! empty( $this->dbh ) && mysql_ping( $this->dbh ) ) {
 				return true;
 			}
 		}
 
 		$error_reporting = false;
 
 		// Disable warnings, as we don't want to see a multitude of "unable to connect" messages.
 		if ( WP_DEBUG ) {
 			$error_reporting = error_reporting();
 			error_reporting( $error_reporting & ~E_WARNING );
 		}
 
 		for ( $tries = 1; $tries <= $this->reconnect_retries; $tries++ ) {
 			// On the last try, re-enable warnings. We want to see a single instance
 			// of the "unable to connect" message on the bail() screen, if it appears.
 			if ( $this->reconnect_retries === $tries && WP_DEBUG ) {
 				error_reporting( $error_reporting );
 			}
 
 			if ( $this->db_connect( false ) ) {
 				if ( $error_reporting ) {
 					error_reporting( $error_reporting );
 				}
 
 				return true;
 			}
 
 			sleep( 1 );
 		}
 
 		// If template_redirect has already happened, it's too late for wp_die()/dead_db().
 		// Let's just return and hope for the best.
 		if ( did_action( 'template_redirect' ) ) {
 			return false;
 		}
 
 		if ( ! $allow_bail ) {
 			return false;
 		}
 
 		wp_load_translations_early();
 
 		$message = '<h1>' . __( 'Error reconnecting to the database' ) . "</h1>\n";
 
 		$message .= '<p>' . sprintf(
 			/* translators: %s: Database host. */
 			__( 'This means that we lost contact with the database server at %s. This could mean your host&#8217;s database server is down.' ),
 			'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
 		) . "</p>\n";
 
 		$message .= "<ul>\n";
 		$message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
 		$message .= '<li>' . __( 'Are you sure the database server is not under particularly heavy load?' ) . "</li>\n";
 		$message .= "</ul>\n";
 
 		$message .= '<p>' . sprintf(
 			/* translators: %s: Support forums URL. */
 			__( 'If you&#8217;re unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress Support Forums</a>.' ),
 			__( 'https://wordpress.org/support/forums/' )
 		) . "</p>\n";
 
 		// We weren't able to reconnect, so we better bail.
 		$this->bail( $message, 'db_connect_fail' );
 
 		// Call dead_db() if bail didn't die, because this database is no more.
 		// It has ceased to be (at least temporarily).
 		dead_db();
 	}
 
 	/**
 	 * Performs a MySQL database query, using current database connection.
 	 *
 	 * More information can be found on the documentation page.
 	 *
 	 * @since 0.71
 	 *
 	 * @link https://developer.wordpress.org/reference/classes/wpdb/
 	 *
 	 * @param string $query Database query.
 	 * @return int|bool Boolean true for CREATE, ALTER, TRUNCATE and DROP queries. Number of rows
 	 *                  affected/selected for all other queries. Boolean false on error.
 	 */
 	public function query( $query ) {
 		if ( ! $this->ready ) {
 			$this->check_current_query = true;
 			return false;
 		}
 
 		/**
 		 * Filters the database query.
 		 *
 		 * Some queries are made before the plugins have been loaded,
 		 * and thus cannot be filtered with this method.
 		 *
 		 * @since 2.1.0
 		 *
 		 * @param string $query Database query.
 		 */
 		$query = apply_filters( 'query', $query );
 
 		if ( ! $query ) {
 			$this->insert_id = 0;
 			return false;
 		}
 
 		$this->flush();
 
 		// Log how the function was called.
 		$this->func_call = "\$db->query(\"$query\")";
 
 		// If we're writing to the database, make sure the query will write safely.
 		if ( $this->check_current_query && ! $this->check_ascii( $query ) ) {
 			$stripped_query = $this->strip_invalid_text_from_query( $query );
 			// strip_invalid_text_from_query() can perform queries, so we need
 			// to flush again, just to make sure everything is clear.
 			$this->flush();
 			if ( $stripped_query !== $query ) {
 				$this->insert_id = 0;
 				return false;
 			}
 		}
 
 		$this->check_current_query = true;
 
 		// Keep track of the last query for debug.
 		$this->last_query = $query;
 
 		$this->_do_query( $query );
 
 		// MySQL server has gone away, try to reconnect.
 		$mysql_errno = 0;
 		if ( ! empty( $this->dbh ) ) {
 			if ( $this->use_mysqli ) {
 				if ( $this->dbh instanceof mysqli ) {
 					$mysql_errno = mysqli_errno( $this->dbh );
 				} else {
 					// $dbh is defined, but isn't a real connection.
 					// Something has gone horribly wrong, let's try a reconnect.
 					$mysql_errno = 2006;
 				}
 			} else {
 				if ( is_resource( $this->dbh ) ) {
 					$mysql_errno = mysql_errno( $this->dbh );
 				} else {
 					$mysql_errno = 2006;
 				}
 			}
 		}
 
 		if ( empty( $this->dbh ) || 2006 === $mysql_errno ) {
 			if ( $this->check_connection() ) {
 				$this->_do_query( $query );
 			} else {
 				$this->insert_id = 0;
 				return false;
 			}
 		}
 
 		// If there is an error then take note of it.
 		if ( $this->use_mysqli ) {
 			if ( $this->dbh instanceof mysqli ) {
 				$this->last_error = mysqli_error( $this->dbh );
 			} else {
 				$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
 			}
 		} else {
 			if ( is_resource( $this->dbh ) ) {
 				$this->last_error = mysql_error( $this->dbh );
 			} else {
 				$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
 			}
 		}
 
 		if ( $this->last_error ) {
 			// Clear insert_id on a subsequent failed insert.
 			if ( $this->insert_id && preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
 				$this->insert_id = 0;
 			}
 
 			$this->print_error();
 			return false;
 		}
 
 		if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
 			$return_val = $this->result;
 		} elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
 			if ( $this->use_mysqli ) {
 				$this->rows_affected = mysqli_affected_rows( $this->dbh );
 			} else {
 				$this->rows_affected = mysql_affected_rows( $this->dbh );
 			}
 			// Take note of the insert_id.
 			if ( preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
 				if ( $this->use_mysqli ) {
 					$this->insert_id = mysqli_insert_id( $this->dbh );
 				} else {
 					$this->insert_id = mysql_insert_id( $this->dbh );
 				}
 			}
 			// Return number of rows affected.
 			$return_val = $this->rows_affected;
 		} else {
 			$num_rows = 0;
 			if ( $this->use_mysqli && $this->result instanceof mysqli_result ) {
 				while ( $row = mysqli_fetch_object( $this->result ) ) {
 					$this->last_result[ $num_rows ] = $row;
 					$num_rows++;
 				}
 			} elseif ( is_resource( $this->result ) ) {
 				while ( $row = mysql_fetch_object( $this->result ) ) {
 					$this->last_result[ $num_rows ] = $row;
 					$num_rows++;
 				}
 			}
 
 			// Log and return the number of rows selected.
 			$this->num_rows = $num_rows;
 			$return_val     = $num_rows;
 		}
 
 		return $return_val;
 	}
 
 	/**
 	 * Internal function to perform the mysql_query() call.
 	 *
 	 * @since 3.9.0
 	 *
 	 * @see wpdb::query()
 	 *
 	 * @param string $query The query to run.
 	 */
 	private function _do_query( $query ) {
 		if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
 			$this->timer_start();
 		}
 
 		if ( ! empty( $this->dbh ) && $this->use_mysqli ) {
 			$this->result = mysqli_query( $this->dbh, $query );
 		} elseif ( ! empty( $this->dbh ) ) {
 			$this->result = mysql_query( $query, $this->dbh );
 		}
 		$this->num_queries++;
 
 		if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
 			$this->log_query(
 				$query,
 				$this->timer_stop(),
 				$this->get_caller(),
 				$this->time_start,
 				array()
 			);
 		}
 	}
 
 	/**
 	 * Logs query data.
 	 *
 	 * @since 5.3.0
 	 *
 	 * @param string $query           The query's SQL.
 	 * @param float  $query_time      Total time spent on the query, in seconds.
 	 * @param string $query_callstack Comma-separated list of the calling functions.
 	 * @param float  $query_start     Unix timestamp of the time at the start of the query.
 	 * @param array  $query_data      Custom query data.
 	 */
 	public function log_query( $query, $query_time, $query_callstack, $query_start, $query_data ) {
 		/**
 		 * Filters the custom data to log alongside a query.
 		 *
 		 * Caution should be used when modifying any of this data, it is recommended that any additional
 		 * information you need to store about a query be added as a new associative array element.
 		 *
 		 * @since 5.3.0
 		 *
 		 * @param array  $query_data      Custom query data.
 		 * @param string $query           The query's SQL.
 		 * @param float  $query_time      Total time spent on the query, in seconds.
 		 * @param string $query_callstack Comma-separated list of the calling functions.
 		 * @param float  $query_start     Unix timestamp of the time at the start of the query.
 		 */
 		$query_data = apply_filters( 'log_query_custom_data', $query_data, $query, $query_time, $query_callstack, $query_start );
 
 		$this->queries[] = array(
 			$query,
 			$query_time,
 			$query_callstack,
 			$query_start,
 			$query_data,
 		);
 	}
 
 	/**
 	 * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
 	 *
 	 * @since 4.8.3
 	 *
 	 * @return string String to escape placeholders.
 	 */
 	public function placeholder_escape() {
 		static $placeholder;
 
 		if ( ! $placeholder ) {
 			// If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
 			$algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
 			// Old WP installs may not have AUTH_SALT defined.
 			$salt = defined( 'AUTH_SALT' ) && AUTH_SALT ? AUTH_SALT : (string) rand();
 
 			$placeholder = '{' . hash_hmac( $algo, uniqid( $salt, true ), $salt ) . '}';
 		}
 
 		/*
 		 * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
 		 * else attached to this filter will receive the query with the placeholder string removed.
 		 */
 		if ( false === has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
 			add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
 		}
 
 		return $placeholder;
 	}
 
 	/**
 	 * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
 	 *
 	 * @since 4.8.3
 	 *
 	 * @param string $query The query to escape.
 	 * @return string The query with the placeholder escape string inserted where necessary.
 	 */
 	public function add_placeholder_escape( $query ) {
 		/*
 		 * To prevent returning anything that even vaguely resembles a placeholder,
 		 * we clobber every % we can find.
 		 */
 		return str_replace( '%', $this->placeholder_escape(), $query );
 	}
 
 	/**
 	 * Removes the placeholder escape strings from a query.
 	 *
 	 * @since 4.8.3
 	 *
 	 * @param string $query The query from which the placeholder will be removed.
 	 * @return string The query with the placeholder removed.
 	 */
 	public function remove_placeholder_escape( $query ) {
 		return str_replace( $this->placeholder_escape(), '%', $query );
 	}
 
 	/**
 	 * Inserts a row into the table.
 	 *
 	 * Examples:
 	 *     wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
 	 *     wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
 	 *
 	 * @since 2.5.0
 	 *
 	 * @see wpdb::prepare()
 	 * @see wpdb::$field_types
 	 * @see wp_set_wpdb_vars()
 	 *
 	 * @param string       $table  Table name.
 	 * @param array        $data   Data to insert (in column => value pairs).
 	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
 	 *                             Sending a null value will cause the column to be set to NULL - the corresponding
 	 *                             format is ignored in this case.
 	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
 	 *                             If string, that format will be used for all of the values in $data.
 	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                             If omitted, all values in $data will be treated as strings unless otherwise
 	 *                             specified in wpdb::$field_types.
 	 * @return int|false The number of rows inserted, or false on error.
 	 */
 	public function insert( $table, $data, $format = null ) {
 		return $this->_insert_replace_helper( $table, $data, $format, 'INSERT' );
 	}
 
 	/**
 	 * Replaces a row in the table.
 	 *
 	 * Examples:
 	 *     wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
 	 *     wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
 	 *
 	 * @since 3.0.0
 	 *
 	 * @see wpdb::prepare()
 	 * @see wpdb::$field_types
 	 * @see wp_set_wpdb_vars()
 	 *
 	 * @param string       $table  Table name.
 	 * @param array        $data   Data to insert (in column => value pairs).
 	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
 	 *                             Sending a null value will cause the column to be set to NULL - the corresponding
 	 *                             format is ignored in this case.
 	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
 	 *                             If string, that format will be used for all of the values in $data.
 	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                             If omitted, all values in $data will be treated as strings unless otherwise
 	 *                             specified in wpdb::$field_types.
 	 * @return int|false The number of rows affected, or false on error.
 	 */
 	public function replace( $table, $data, $format = null ) {
 		return $this->_insert_replace_helper( $table, $data, $format, 'REPLACE' );
 	}
 
 	/**
 	 * Helper function for insert and replace.
 	 *
 	 * Runs an insert or replace query based on $type argument.
 	 *
 	 * @since 3.0.0
 	 *
 	 * @see wpdb::prepare()
 	 * @see wpdb::$field_types
 	 * @see wp_set_wpdb_vars()
 	 *
 	 * @param string       $table  Table name.
 	 * @param array        $data   Data to insert (in column => value pairs).
 	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
 	 *                             Sending a null value will cause the column to be set to NULL - the corresponding
 	 *                             format is ignored in this case.
 	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
 	 *                             If string, that format will be used for all of the values in $data.
 	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                             If omitted, all values in $data will be treated as strings unless otherwise
 	 *                             specified in wpdb::$field_types.
 	 * @param string       $type   Optional. Type of operation. Possible values include 'INSERT' or 'REPLACE'.
 	 *                             Default 'INSERT'.
 	 * @return int|false The number of rows affected, or false on error.
 	 */
 	function _insert_replace_helper( $table, $data, $format = null, $type = 'INSERT' ) {
 		$this->insert_id = 0;
 
 		if ( ! in_array( strtoupper( $type ), array( 'REPLACE', 'INSERT' ), true ) ) {
 			return false;
 		}
 
 		$data = $this->process_fields( $table, $data, $format );
 		if ( false === $data ) {
 			return false;
 		}
 
 		$formats = array();
 		$values  = array();
 		foreach ( $data as $value ) {
 			if ( is_null( $value['value'] ) ) {
 				$formats[] = 'NULL';
 				continue;
 			}
 
 			$formats[] = $value['format'];
 			$values[]  = $value['value'];
 		}
 
 		$fields  = '`' . implode( '`, `', array_keys( $data ) ) . '`';
 		$formats = implode( ', ', $formats );
 
 		$sql = "$type INTO `$table` ($fields) VALUES ($formats)";
 
 		$this->check_current_query = false;
 		return $this->query( $this->prepare( $sql, $values ) );
 	}
 
 	/**
 	 * Updates a row in the table.
 	 *
 	 * Examples:
 	 *     wpdb::update( 'table', array( 'column' => 'foo', 'field' => 'bar' ), array( 'ID' => 1 ) )
 	 *     wpdb::update( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( 'ID' => 1 ), array( '%s', '%d' ), array( '%d' ) )
 	 *
 	 * @since 2.5.0
 	 *
 	 * @see wpdb::prepare()
 	 * @see wpdb::$field_types
 	 * @see wp_set_wpdb_vars()
 	 *
 	 * @param string       $table        Table name.
 	 * @param array        $data         Data to update (in column => value pairs).
 	 *                                   Both $data columns and $data values should be "raw" (neither should be SQL escaped).
 	 *                                   Sending a null value will cause the column to be set to NULL - the corresponding
 	 *                                   format is ignored in this case.
 	 * @param array        $where        A named array of WHERE clauses (in column => value pairs).
 	 *                                   Multiple clauses will be joined with ANDs.
 	 *                                   Both $where columns and $where values should be "raw".
 	 *                                   Sending a null value will create an IS NULL comparison - the corresponding
 	 *                                   format will be ignored in this case.
 	 * @param array|string $format       Optional. An array of formats to be mapped to each of the values in $data.
 	 *                                   If string, that format will be used for all of the values in $data.
 	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                                   If omitted, all values in $data will be treated as strings unless otherwise
 	 *                                   specified in wpdb::$field_types.
 	 * @param array|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
 	 *                                   If string, that format will be used for all of the items in $where.
 	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                                   If omitted, all values in $where will be treated as strings.
 	 * @return int|false The number of rows updated, or false on error.
 	 */
 	public function update( $table, $data, $where, $format = null, $where_format = null ) {
 		if ( ! is_array( $data ) || ! is_array( $where ) ) {
 			return false;
 		}
 
 		$data = $this->process_fields( $table, $data, $format );
 		if ( false === $data ) {
 			return false;
 		}
 		$where = $this->process_fields( $table, $where, $where_format );
 		if ( false === $where ) {
 			return false;
 		}
 
 		$fields     = array();
 		$conditions = array();
 		$values     = array();
 		foreach ( $data as $field => $value ) {
 			if ( is_null( $value['value'] ) ) {
 				$fields[] = "`$field` = NULL";
 				continue;
 			}
 
 			$fields[] = "`$field` = " . $value['format'];
 			$values[] = $value['value'];
 		}
 		foreach ( $where as $field => $value ) {
 			if ( is_null( $value['value'] ) ) {
 				$conditions[] = "`$field` IS NULL";
 				continue;
 			}
 
 			$conditions[] = "`$field` = " . $value['format'];
 			$values[]     = $value['value'];
 		}
 
 		$fields     = implode( ', ', $fields );
 		$conditions = implode( ' AND ', $conditions );
 
 		$sql = "UPDATE `$table` SET $fields WHERE $conditions";
 
 		$this->check_current_query = false;
 		return $this->query( $this->prepare( $sql, $values ) );
 	}
 
 	/**
 	 * Deletes a row in the table.
 	 *
 	 * Examples:
 	 *     wpdb::delete( 'table', array( 'ID' => 1 ) )
 	 *     wpdb::delete( 'table', array( 'ID' => 1 ), array( '%d' ) )
 	 *
 	 * @since 3.4.0
 	 *
 	 * @see wpdb::prepare()
 	 * @see wpdb::$field_types
 	 * @see wp_set_wpdb_vars()
 	 *
 	 * @param string       $table        Table name.
 	 * @param array        $where        A named array of WHERE clauses (in column => value pairs).
 	 *                                   Multiple clauses will be joined with ANDs.
 	 *                                   Both $where columns and $where values should be "raw".
 	 *                                   Sending a null value will create an IS NULL comparison - the corresponding
 	 *                                   format will be ignored in this case.
 	 * @param array|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
 	 *                                   If string, that format will be used for all of the items in $where.
 	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
 	 *                                   If omitted, all values in $data will be treated as strings unless otherwise
 	 *                                   specified in wpdb::$field_types.
 	 * @return int|false The number of rows updated, or false on error.
 	 */
 	public function delete( $table, $where, $where_format = null ) {
 		if ( ! is_array( $where ) ) {
 			return false;
 		}
 
 		$where = $this->process_fields( $table, $where, $where_format );
 		if ( false === $where ) {
 			return false;
 		}
 
 		$conditions = array();
 		$values     = array();
 		foreach ( $where as $field => $value ) {
 			if ( is_null( $value['value'] ) ) {
 				$conditions[] = "`$field` IS NULL";
 				continue;
 			}
 
 			$conditions[] = "`$field` = " . $value['format'];
 			$values[]     = $value['value'];
 		}
 
 		$conditions = implode( ' AND ', $conditions );
 
 		$sql = "DELETE FROM `$table` WHERE $conditions";
 
 		$this->check_current_query = false;
 		return $this->query( $this->prepare( $sql, $values ) );
 	}
 
 	/**
 	 * Processes arrays of field/value pairs and field formats.
 	 *
 	 * This is a helper method for wpdb's CRUD methods, which take field/value pairs
 	 * for inserts, updates, and where clauses. This method first pairs each value
 	 * with a format. Then it determines the charset of that field, using that
 	 * to determine if any invalid text would be stripped. If text is stripped,
 	 * then field processing is rejected and the query fails.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $table  Table name.
 	 * @param array  $data   Field/value pair.
 	 * @param mixed  $format Format for each field.
 	 * @return array|false An array of fields that contain paired value and formats.
 	 *                     False for invalid values.
 	 */
 	protected function process_fields( $table, $data, $format ) {
 		$data = $this->process_field_formats( $data, $format );
 		if ( false === $data ) {
 			return false;
 		}
 
 		$data = $this->process_field_charsets( $data, $table );
 		if ( false === $data ) {
 			return false;
 		}
 
 		$data = $this->process_field_lengths( $data, $table );
 		if ( false === $data ) {
 			return false;
 		}
 
 		$converted_data = $this->strip_invalid_text( $data );
 
 		if ( $data !== $converted_data ) {
 			return false;
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param array $data   Array of fields to values.
 	 * @param mixed $format Formats to be mapped to the values in $data.
 	 * @return array Array, keyed by field names with values being an array
 	 *               of 'value' and 'format' keys.
 	 */
 	protected function process_field_formats( $data, $format ) {
 		$formats          = (array) $format;
 		$original_formats = $formats;
 
 		foreach ( $data as $field => $value ) {
 			$value = array(
 				'value'  => $value,
 				'format' => '%s',
 			);
 
 			if ( ! empty( $format ) ) {
 				$value['format'] = array_shift( $formats );
 				if ( ! $value['format'] ) {
 					$value['format'] = reset( $original_formats );
 				}
 			} elseif ( isset( $this->field_types[ $field ] ) ) {
 				$value['format'] = $this->field_types[ $field ];
 			}
 
 			$data[ $field ] = $value;
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Adds field charsets to field/value/format arrays generated by wpdb::process_field_formats().
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param array  $data  As it comes from the wpdb::process_field_formats() method.
 	 * @param string $table Table name.
 	 * @return array|false The same array as $data with additional 'charset' keys.
 	 *                     False on failure.
 	 */
 	protected function process_field_charsets( $data, $table ) {
 		foreach ( $data as $field => $value ) {
 			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
 				/*
 				 * We can skip this field if we know it isn't a string.
 				 * This checks %d/%f versus ! %s because its sprintf() could take more.
 				 */
 				$value['charset'] = false;
 			} else {
 				$value['charset'] = $this->get_col_charset( $table, $field );
 				if ( is_wp_error( $value['charset'] ) ) {
 					return false;
 				}
 			}
 
 			$data[ $field ] = $value;
 		}
 
 		return $data;
 	}
 
 	/**
 	 * For string fields, records the maximum string length that field can safely save.
 	 *
 	 * @since 4.2.1
 	 *
 	 * @param array  $data  As it comes from the wpdb::process_field_charsets() method.
 	 * @param string $table Table name.
 	 * @return array|false The same array as $data with additional 'length' keys, or false if
 	 *                     any of the values were too long for their corresponding field.
 	 */
 	protected function process_field_lengths( $data, $table ) {
 		foreach ( $data as $field => $value ) {
 			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
 				/*
 				 * We can skip this field if we know it isn't a string.
 				 * This checks %d/%f versus ! %s because its sprintf() could take more.
 				 */
 				$value['length'] = false;
 			} else {
 				$value['length'] = $this->get_col_length( $table, $field );
 				if ( is_wp_error( $value['length'] ) ) {
 					return false;
 				}
 			}
 
 			$data[ $field ] = $value;
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Retrieves one variable from the database.
 	 *
 	 * Executes a SQL query and returns the value from the SQL result.
 	 * If the SQL result contains more than one column and/or more than one row,
 	 * the value in the column and row specified is returned. If $query is null,
 	 * the value in the specified column and row from the previous SQL result is returned.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string|null $query Optional. SQL query. Defaults to null, use the result from the previous query.
 	 * @param int         $x     Optional. Column of value to return. Indexed from 0.
 	 * @param int         $y     Optional. Row of value to return. Indexed from 0.
 	 * @return string|null Database query result (as string), or null on failure.
 	 */
 	public function get_var( $query = null, $x = 0, $y = 0 ) {
 		$this->func_call = "\$db->get_var(\"$query\", $x, $y)";
 
 		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
 			$this->check_current_query = false;
 		}
 
 		if ( $query ) {
 			$this->query( $query );
 		}
 
 		// Extract var out of cached results based on x,y vals.
 		if ( ! empty( $this->last_result[ $y ] ) ) {
 			$values = array_values( get_object_vars( $this->last_result[ $y ] ) );
 		}
 
 		// If there is a value return it, else return null.
 		return ( isset( $values[ $x ] ) && '' !== $values[ $x ] ) ? $values[ $x ] : null;
 	}
 
 	/**
 	 * Retrieves one row from the database.
 	 *
 	 * Executes a SQL query and returns the row from the SQL result.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string|null $query  SQL query.
 	 * @param string      $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
 	 *                            correspond to an stdClass object, an associative array, or a numeric array,
 	 *                            respectively. Default OBJECT.
 	 * @param int         $y      Optional. Row to return. Indexed from 0.
 	 * @return array|object|null|void Database query result in format specified by $output or null on failure.
 	 */
 	public function get_row( $query = null, $output = OBJECT, $y = 0 ) {
 		$this->func_call = "\$db->get_row(\"$query\",$output,$y)";
 
 		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
 			$this->check_current_query = false;
 		}
 
 		if ( $query ) {
 			$this->query( $query );
 		} else {
 			return null;
 		}
 
 		if ( ! isset( $this->last_result[ $y ] ) ) {
 			return null;
 		}
 
 		if ( OBJECT === $output ) {
 			return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
 		} elseif ( ARRAY_A === $output ) {
 			return $this->last_result[ $y ] ? get_object_vars( $this->last_result[ $y ] ) : null;
 		} elseif ( ARRAY_N === $output ) {
 			return $this->last_result[ $y ] ? array_values( get_object_vars( $this->last_result[ $y ] ) ) : null;
 		} elseif ( OBJECT === strtoupper( $output ) ) {
 			// Back compat for OBJECT being previously case-insensitive.
 			return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
 		} else {
 			$this->print_error( ' $db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N' );
 		}
 	}
 
 	/**
 	 * Retrieves one column from the database.
 	 *
 	 * Executes a SQL query and returns the column from the SQL result.
 	 * If the SQL result contains more than one column, the column specified is returned.
 	 * If $query is null, the specified column from the previous SQL result is returned.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string|null $query Optional. SQL query. Defaults to previous query.
 	 * @param int         $x     Optional. Column to return. Indexed from 0.
 	 * @return array Database query result. Array indexed from 0 by SQL result row number.
 	 */
 	public function get_col( $query = null, $x = 0 ) {
 		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
 			$this->check_current_query = false;
 		}
 
 		if ( $query ) {
 			$this->query( $query );
 		}
 
 		$new_array = array();
 		// Extract the column values.
 		if ( $this->last_result ) {
 			for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
 				$new_array[ $i ] = $this->get_var( null, $x, $i );
 			}
 		}
 		return $new_array;
 	}
 
 	/**
 	 * Retrieves an entire SQL result set from the database (i.e., many rows).
 	 *
 	 * Executes a SQL query and returns the entire SQL result.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string $query  SQL query.
 	 * @param string $output Optional. Any of ARRAY_A | ARRAY_N | OBJECT | OBJECT_K constants.
 	 *                       With one of the first three, return an array of rows indexed
 	 *                       from 0 by SQL result row number. Each row is an associative array
 	 *                       (column => value, ...), a numerically indexed array (0 => value, ...),
 	 *                       or an object ( ->column = value ), respectively. With OBJECT_K,
 	 *                       return an associative array of row objects keyed by the value
 	 *                       of each row's first column's value. Duplicate keys are discarded.
 	 * @return array|object|null Database query results.
 	 */
 	public function get_results( $query = null, $output = OBJECT ) {
 		$this->func_call = "\$db->get_results(\"$query\", $output)";
 
 		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
 			$this->check_current_query = false;
 		}
 
 		if ( $query ) {
 			$this->query( $query );
 		} else {
 			return null;
 		}
 
 		$new_array = array();
 		if ( OBJECT === $output ) {
 			// Return an integer-keyed array of row objects.
 			return $this->last_result;
 		} elseif ( OBJECT_K === $output ) {
 			// Return an array of row objects with keys from column 1.
 			// (Duplicates are discarded.)
 			if ( $this->last_result ) {
 				foreach ( $this->last_result as $row ) {
 					$var_by_ref = get_object_vars( $row );
 					$key        = array_shift( $var_by_ref );
 					if ( ! isset( $new_array[ $key ] ) ) {
 						$new_array[ $key ] = $row;
 					}
 				}
 			}
 			return $new_array;
 		} elseif ( ARRAY_A === $output || ARRAY_N === $output ) {
 			// Return an integer-keyed array of...
 			if ( $this->last_result ) {
 				foreach ( (array) $this->last_result as $row ) {
 					if ( ARRAY_N === $output ) {
 						// ...integer-keyed row arrays.
 						$new_array[] = array_values( get_object_vars( $row ) );
 					} else {
 						// ...column name-keyed row arrays.
 						$new_array[] = get_object_vars( $row );
 					}
 				}
 			}
 			return $new_array;
 		} elseif ( strtoupper( $output ) === OBJECT ) {
 			// Back compat for OBJECT being previously case-insensitive.
 			return $this->last_result;
 		}
 		return null;
 	}
 
 	/**
 	 * Retrieves the character set for the given table.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $table Table name.
 	 * @return string|WP_Error Table character set, WP_Error object if it couldn't be found.
 	 */
 	protected function get_table_charset( $table ) {
 		$tablekey = strtolower( $table );
 
 		/**
 		 * Filters the table charset value before the DB is checked.
 		 *
 		 * Passing a non-null value to the filter will effectively short-circuit
 		 * checking the DB for the charset, returning that value instead.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @param string|null $charset The character set to use. Default null.
 		 * @param string      $table   The name of the table being checked.
 		 */
 		$charset = apply_filters( 'pre_get_table_charset', null, $table );
 		if ( null !== $charset ) {
 			return $charset;
 		}
 
 		if ( isset( $this->table_charset[ $tablekey ] ) ) {
 			return $this->table_charset[ $tablekey ];
 		}
 
 		$charsets = array();
 		$columns  = array();
 
 		$table_parts = explode( '.', $table );
 		$table       = '`' . implode( '`.`', $table_parts ) . '`';
 		$results     = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
 		if ( ! $results ) {
 			return new WP_Error( 'wpdb_get_table_charset_failure' );
 		}
 
 		foreach ( $results as $column ) {
 			$columns[ strtolower( $column->Field ) ] = $column;
 		}
 
 		$this->col_meta[ $tablekey ] = $columns;
 
 		foreach ( $columns as $column ) {
 			if ( ! empty( $column->Collation ) ) {
 				list( $charset ) = explode( '_', $column->Collation );
 
 				// If the current connection can't support utf8mb4 characters, let's only send 3-byte utf8 characters.
 				if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
 					$charset = 'utf8';
 				}
 
 				$charsets[ strtolower( $charset ) ] = true;
 			}
 
 			list( $type ) = explode( '(', $column->Type );
 
 			// A binary/blob means the whole query gets treated like this.
 			if ( in_array( strtoupper( $type ), array( 'BINARY', 'VARBINARY', 'TINYBLOB', 'MEDIUMBLOB', 'BLOB', 'LONGBLOB' ), true ) ) {
 				$this->table_charset[ $tablekey ] = 'binary';
 				return 'binary';
 			}
 		}
 
 		// utf8mb3 is an alias for utf8.
 		if ( isset( $charsets['utf8mb3'] ) ) {
 			$charsets['utf8'] = true;
 			unset( $charsets['utf8mb3'] );
 		}
 
 		// Check if we have more than one charset in play.
 		$count = count( $charsets );
 		if ( 1 === $count ) {
 			$charset = key( $charsets );
 		} elseif ( 0 === $count ) {
 			// No charsets, assume this table can store whatever.
 			$charset = false;
 		} else {
 			// More than one charset. Remove latin1 if present and recalculate.
 			unset( $charsets['latin1'] );
 			$count = count( $charsets );
 			if ( 1 === $count ) {
 				// Only one charset (besides latin1).
 				$charset = key( $charsets );
 			} elseif ( 2 === $count && isset( $charsets['utf8'], $charsets['utf8mb4'] ) ) {
 				// Two charsets, but they're utf8 and utf8mb4, use utf8.
 				$charset = 'utf8';
 			} else {
 				// Two mixed character sets. ascii.
 				$charset = 'ascii';
 			}
 		}
 
 		$this->table_charset[ $tablekey ] = $charset;
 		return $charset;
 	}
 
 	/**
 	 * Retrieves the character set for the given column.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $table  Table name.
 	 * @param string $column Column name.
 	 * @return string|false|WP_Error Column character set as a string. False if the column has
 	 *                               no character set. WP_Error object if there was an error.
 	 */
 	public function get_col_charset( $table, $column ) {
 		$tablekey  = strtolower( $table );
 		$columnkey = strtolower( $column );
 
 		/**
 		 * Filters the column charset value before the DB is checked.
 		 *
 		 * Passing a non-null value to the filter will short-circuit
 		 * checking the DB for the charset, returning that value instead.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @param string|null $charset The character set to use. Default null.
 		 * @param string      $table   The name of the table being checked.
 		 * @param string      $column  The name of the column being checked.
 		 */
 		$charset = apply_filters( 'pre_get_col_charset', null, $table, $column );
 		if ( null !== $charset ) {
 			return $charset;
 		}
 
 		// Skip this entirely if this isn't a MySQL database.
 		if ( empty( $this->is_mysql ) ) {
 			return false;
 		}
 
 		if ( empty( $this->table_charset[ $tablekey ] ) ) {
 			// This primes column information for us.
 			$table_charset = $this->get_table_charset( $table );
 			if ( is_wp_error( $table_charset ) ) {
 				return $table_charset;
 			}
 		}
 
 		// If still no column information, return the table charset.
 		if ( empty( $this->col_meta[ $tablekey ] ) ) {
 			return $this->table_charset[ $tablekey ];
 		}
 
 		// If this column doesn't exist, return the table charset.
 		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
 			return $this->table_charset[ $tablekey ];
 		}
 
 		// Return false when it's not a string column.
 		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) {
 			return false;
 		}
 
 		list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation );
 		return $charset;
 	}
 
 	/**
 	 * Retrieves the maximum string length allowed in a given column.
 	 *
 	 * The length may either be specified as a byte length or a character length.
 	 *
 	 * @since 4.2.1
 	 *
 	 * @param string $table  Table name.
 	 * @param string $column Column name.
 	 * @return array|false|WP_Error array( 'length' => (int), 'type' => 'byte' | 'char' ).
 	 *                              False if the column has no length (for example, numeric column).
 	 *                              WP_Error object if there was an error.
 	 */
 	public function get_col_length( $table, $column ) {
 		$tablekey  = strtolower( $table );
 		$columnkey = strtolower( $column );
 
 		// Skip this entirely if this isn't a MySQL database.
 		if ( empty( $this->is_mysql ) ) {
 			return false;
 		}
 
 		if ( empty( $this->col_meta[ $tablekey ] ) ) {
 			// This primes column information for us.
 			$table_charset = $this->get_table_charset( $table );
 			if ( is_wp_error( $table_charset ) ) {
 				return $table_charset;
 			}
 		}
 
 		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
 			return false;
 		}
 
 		$typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );
 
 		$type = strtolower( $typeinfo[0] );
 		if ( ! empty( $typeinfo[1] ) ) {
 			$length = trim( $typeinfo[1], ')' );
 		} else {
 			$length = false;
 		}
 
 		switch ( $type ) {
 			case 'char':
 			case 'varchar':
 				return array(
 					'type'   => 'char',
 					'length' => (int) $length,
 				);
 
 			case 'binary':
 			case 'varbinary':
 				return array(
 					'type'   => 'byte',
 					'length' => (int) $length,
 				);
 
 			case 'tinyblob':
 			case 'tinytext':
 				return array(
 					'type'   => 'byte',
 					'length' => 255,        // 2^8 - 1
 				);
 
 			case 'blob':
 			case 'text':
 				return array(
 					'type'   => 'byte',
 					'length' => 65535,      // 2^16 - 1
 				);
 
 			case 'mediumblob':
 			case 'mediumtext':
 				return array(
 					'type'   => 'byte',
 					'length' => 16777215,   // 2^24 - 1
 				);
 
 			case 'longblob':
 			case 'longtext':
 				return array(
 					'type'   => 'byte',
 					'length' => 4294967295, // 2^32 - 1
 				);
 
 			default:
 				return false;
 		}
 	}
 
 	/**
 	 * Checks if a string is ASCII.
 	 *
 	 * The negative regex is faster for non-ASCII strings, as it allows
 	 * the search to finish as soon as it encounters a non-ASCII character.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $string String to check.
 	 * @return bool True if ASCII, false if not.
 	 */
 	protected function check_ascii( $string ) {
 		if ( function_exists( 'mb_check_encoding' ) ) {
 			if ( mb_check_encoding( $string, 'ASCII' ) ) {
 				return true;
 			}
 		} elseif ( ! preg_match( '/[^\x00-\x7F]/', $string ) ) {
 			return true;
 		}
 
 		return false;
 	}
 
 	/**
 	 * Checks if the query is accessing a collation considered safe on the current version of MySQL.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $query The query to check.
 	 * @return bool True if the collation is safe, false if it isn't.
 	 */
 	protected function check_safe_collation( $query ) {
 		if ( $this->checking_collation ) {
 			return true;
 		}
 
 		// We don't need to check the collation for queries that don't read data.
 		$query = ltrim( $query, "\r\n\t (" );
 		if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $query ) ) {
 			return true;
 		}
 
 		// All-ASCII queries don't need extra checking.
 		if ( $this->check_ascii( $query ) ) {
 			return true;
 		}
 
 		$table = $this->get_table_from_query( $query );
 		if ( ! $table ) {
 			return false;
 		}
 
 		$this->checking_collation = true;
 		$collation                = $this->get_table_charset( $table );
 		$this->checking_collation = false;
 
 		// Tables with no collation, or latin1 only, don't need extra checking.
 		if ( false === $collation || 'latin1' === $collation ) {
 			return true;
 		}
 
 		$table = strtolower( $table );
 		if ( empty( $this->col_meta[ $table ] ) ) {
 			return false;
 		}
 
 		// If any of the columns don't have one of these collations, it needs more sanity checking.
 		foreach ( $this->col_meta[ $table ] as $col ) {
 			if ( empty( $col->Collation ) ) {
 				continue;
 			}
 
 			if ( ! in_array( $col->Collation, array( 'utf8_general_ci', 'utf8_bin', 'utf8mb4_general_ci', 'utf8mb4_bin' ), true ) ) {
 				return false;
 			}
 		}
 
 		return true;
 	}
 
 	/**
 	 * Strips any invalid characters based on value/charset pairs.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param array $data Array of value arrays. Each value array has the keys 'value' and 'charset'.
 	 *                    An optional 'ascii' key can be set to false to avoid redundant ASCII checks.
 	 * @return array|WP_Error The $data parameter, with invalid characters removed from each value.
 	 *                        This works as a passthrough: any additional keys such as 'field' are
 	 *                        retained in each value array. If we cannot remove invalid characters,
 	 *                        a WP_Error object is returned.
 	 */
 	protected function strip_invalid_text( $data ) {
 		$db_check_string = false;
 
 		foreach ( $data as &$value ) {
 			$charset = $value['charset'];
 
 			if ( is_array( $value['length'] ) ) {
 				$length                  = $value['length']['length'];
 				$truncate_by_byte_length = 'byte' === $value['length']['type'];
 			} else {
 				$length = false;
 				// Since we have no length, we'll never truncate. Initialize the variable to false.
 				// True would take us through an unnecessary (for this case) codepath below.
 				$truncate_by_byte_length = false;
 			}
 
 			// There's no charset to work with.
 			if ( false === $charset ) {
 				continue;
 			}
 
 			// Column isn't a string.
 			if ( ! is_string( $value['value'] ) ) {
 				continue;
 			}
 
 			$needs_validation = true;
 			if (
 				// latin1 can store any byte sequence.
 				'latin1' === $charset
 			||
 				// ASCII is always OK.
 				( ! isset( $value['ascii'] ) && $this->check_ascii( $value['value'] ) )
 			) {
 				$truncate_by_byte_length = true;
 				$needs_validation        = false;
 			}
 
 			if ( $truncate_by_byte_length ) {
 				mbstring_binary_safe_encoding();
 				if ( false !== $length && strlen( $value['value'] ) > $length ) {
 					$value['value'] = substr( $value['value'], 0, $length );
 				}
 				reset_mbstring_encoding();
 
 				if ( ! $needs_validation ) {
 					continue;
 				}
 			}
 
 			// utf8 can be handled by regex, which is a bunch faster than a DB lookup.
 			if ( ( 'utf8' === $charset || 'utf8mb3' === $charset || 'utf8mb4' === $charset ) && function_exists( 'mb_strlen' ) ) {
 				$regex = '/
 					(
 						(?: [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
 						|   [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
 						|   \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
 						|   [\xE1-\xEC][\x80-\xBF]{2}
 						|   \xED[\x80-\x9F][\x80-\xBF]
 						|   [\xEE-\xEF][\x80-\xBF]{2}';
 
 				if ( 'utf8mb4' === $charset ) {
 					$regex .= '
 						|    \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
 						|    [\xF1-\xF3][\x80-\xBF]{3}
 						|    \xF4[\x80-\x8F][\x80-\xBF]{2}
 					';
 				}
 
 				$regex         .= '){1,40}                          # ...one or more times
 					)
 					| .                                  # anything else
 					/x';
 				$value['value'] = preg_replace( $regex, '$1', $value['value'] );
 
 				if ( false !== $length && mb_strlen( $value['value'], 'UTF-8' ) > $length ) {
 					$value['value'] = mb_substr( $value['value'], 0, $length, 'UTF-8' );
 				}
 				continue;
 			}
 
 			// We couldn't use any local conversions, send it to the DB.
 			$value['db']     = true;
 			$db_check_string = true;
 		}
 		unset( $value ); // Remove by reference.
 
 		if ( $db_check_string ) {
 			$queries = array();
 			foreach ( $data as $col => $value ) {
 				if ( ! empty( $value['db'] ) ) {
 					// We're going to need to truncate by characters or bytes, depending on the length value we have.
 					if ( isset( $value['length']['type'] ) && 'byte' === $value['length']['type'] ) {
 						// Using binary causes LEFT() to truncate by bytes.
 						$charset = 'binary';
 					} else {
 						$charset = $value['charset'];
 					}
 
 					if ( $this->charset ) {
 						$connection_charset = $this->charset;
 					} else {
 						if ( $this->use_mysqli ) {
 							$connection_charset = mysqli_character_set_name( $this->dbh );
 						} else {
 							$connection_charset = mysql_client_encoding();
 						}
 					}
 
 					if ( is_array( $value['length'] ) ) {
 						$length          = sprintf( '%.0f', $value['length']['length'] );
 						$queries[ $col ] = $this->prepare( "CONVERT( LEFT( CONVERT( %s USING $charset ), $length ) USING $connection_charset )", $value['value'] );
 					} elseif ( 'binary' !== $charset ) {
 						// If we don't have a length, there's no need to convert binary - it will always return the same result.
 						$queries[ $col ] = $this->prepare( "CONVERT( CONVERT( %s USING $charset ) USING $connection_charset )", $value['value'] );
 					}
 
 					unset( $data[ $col ]['db'] );
 				}
 			}
 
 			$sql = array();
 			foreach ( $queries as $column => $query ) {
 				if ( ! $query ) {
 					continue;
 				}
 
 				$sql[] = $query . " AS x_$column";
 			}
 
 			$this->check_current_query = false;
 			$row                       = $this->get_row( 'SELECT ' . implode( ', ', $sql ), ARRAY_A );
 			if ( ! $row ) {
 				return new WP_Error( 'wpdb_strip_invalid_text_failure' );
 			}
 
 			foreach ( array_keys( $data ) as $column ) {
 				if ( isset( $row[ "x_$column" ] ) ) {
 					$data[ $column ]['value'] = $row[ "x_$column" ];
 				}
 			}
 		}
 
 		return $data;
 	}
 
 	/**
 	 * Strips any invalid characters from the query.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $query Query to convert.
 	 * @return string|WP_Error The converted query, or a WP_Error object if the conversion fails.
 	 */
 	protected function strip_invalid_text_from_query( $query ) {
 		// We don't need to check the collation for queries that don't read data.
 		$trimmed_query = ltrim( $query, "\r\n\t (" );
 		if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $trimmed_query ) ) {
 			return $query;
 		}
 
 		$table = $this->get_table_from_query( $query );
 		if ( $table ) {
 			$charset = $this->get_table_charset( $table );
 			if ( is_wp_error( $charset ) ) {
 				return $charset;
 			}
 
 			// We can't reliably strip text from tables containing binary/blob columns.
 			if ( 'binary' === $charset ) {
 				return $query;
 			}
 		} else {
 			$charset = $this->charset;
 		}
 
 		$data = array(
 			'value'   => $query,
 			'charset' => $charset,
 			'ascii'   => false,
 			'length'  => false,
 		);
 
 		$data = $this->strip_invalid_text( array( $data ) );
 		if ( is_wp_error( $data ) ) {
 			return $data;
 		}
 
 		return $data[0]['value'];
 	}
 
 	/**
 	 * Strips any invalid characters from the string for a given table and column.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $table  Table name.
 	 * @param string $column Column name.
 	 * @param string $value  The text to check.
 	 * @return string|WP_Error The converted string, or a WP_Error object if the conversion fails.
 	 */
 	public function strip_invalid_text_for_column( $table, $column, $value ) {
 		if ( ! is_string( $value ) ) {
 			return $value;
 		}
 
 		$charset = $this->get_col_charset( $table, $column );
 		if ( ! $charset ) {
 			// Not a string column.
 			return $value;
 		} elseif ( is_wp_error( $charset ) ) {
 			// Bail on real errors.
 			return $charset;
 		}
 
 		$data = array(
 			$column => array(
 				'value'   => $value,
 				'charset' => $charset,
 				'length'  => $this->get_col_length( $table, $column ),
 			),
 		);
 
 		$data = $this->strip_invalid_text( $data );
 		if ( is_wp_error( $data ) ) {
 			return $data;
 		}
 
 		return $data[ $column ]['value'];
 	}
 
 	/**
 	 * Finds the first table name referenced in a query.
 	 *
 	 * @since 4.2.0
 	 *
 	 * @param string $query The query to search.
 	 * @return string|false The table name found, or false if a table couldn't be found.
 	 */
 	protected function get_table_from_query( $query ) {
 		// Remove characters that can legally trail the table name.
 		$query = rtrim( $query, ';/-#' );
 
 		// Allow (select...) union [...] style queries. Use the first query's table name.
 		$query = ltrim( $query, "\r\n\t (" );
 
 		// Strip everything between parentheses except nested selects.
 		$query = preg_replace( '/\((?!\s*select)[^(]*?\)/is', '()', $query );
 
 		// Quickly match most common queries.
 		if ( preg_match(
 			'/^\s*(?:'
 				. 'SELECT.*?\s+FROM'
 				. '|INSERT(?:\s+LOW_PRIORITY|\s+DELAYED|\s+HIGH_PRIORITY)?(?:\s+IGNORE)?(?:\s+INTO)?'
 				. '|REPLACE(?:\s+LOW_PRIORITY|\s+DELAYED)?(?:\s+INTO)?'
 				. '|UPDATE(?:\s+LOW_PRIORITY)?(?:\s+IGNORE)?'
 				. '|DELETE(?:\s+LOW_PRIORITY|\s+QUICK|\s+IGNORE)*(?:.+?FROM)?'
 			. ')\s+((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)/is',
 			$query,
 			$maybe
 		) ) {
 			return str_replace( '`', '', $maybe[1] );
 		}
 
 		// SHOW TABLE STATUS and SHOW TABLES WHERE Name = 'wp_posts'
 		if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES).+WHERE\s+Name\s*=\s*("|\')((?:[0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)\\1/is', $query, $maybe ) ) {
 			return $maybe[2];
 		}
 
 		/*
 		 * SHOW TABLE STATUS LIKE and SHOW TABLES LIKE 'wp\_123\_%'
 		 * This quoted LIKE operand seldom holds a full table name.
 		 * It is usually a pattern for matching a prefix so we just
 		 * strip the trailing % and unescape the _ to get 'wp_123_'
 		 * which drop-ins can use for routing these SQL statements.
 		 */
 		if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES)\s+(?:WHERE\s+Name\s+)?LIKE\s*("|\')((?:[\\\\0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)%?\\1/is', $query, $maybe ) ) {
 			return str_replace( '\\_', '_', $maybe[2] );
 		}
 
 		// Big pattern for the rest of the table-related queries.
 		if ( preg_match(
 			'/^\s*(?:'
 				. '(?:EXPLAIN\s+(?:EXTENDED\s+)?)?SELECT.*?\s+FROM'
 				. '|DESCRIBE|DESC|EXPLAIN|HANDLER'
 				. '|(?:LOCK|UNLOCK)\s+TABLE(?:S)?'
 				. '|(?:RENAME|OPTIMIZE|BACKUP|RESTORE|CHECK|CHECKSUM|ANALYZE|REPAIR).*\s+TABLE'
 				. '|TRUNCATE(?:\s+TABLE)?'
 				. '|CREATE(?:\s+TEMPORARY)?\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?'
 				. '|ALTER(?:\s+IGNORE)?\s+TABLE'
 				. '|DROP\s+TABLE(?:\s+IF\s+EXISTS)?'
 				. '|CREATE(?:\s+\w+)?\s+INDEX.*\s+ON'
 				. '|DROP\s+INDEX.*\s+ON'
 				. '|LOAD\s+DATA.*INFILE.*INTO\s+TABLE'
 				. '|(?:GRANT|REVOKE).*ON\s+TABLE'
 				. '|SHOW\s+(?:.*FROM|.*TABLE)'
 			. ')\s+\(*\s*((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)\s*\)*/is',
 			$query,
 			$maybe
 		) ) {
 			return str_replace( '`', '', $maybe[1] );
 		}
 
 		return false;
 	}
 
 	/**
 	 * Loads the column metadata from the last query.
 	 *
 	 * @since 3.5.0
 	 */
 	protected function load_col_info() {
 		if ( $this->col_info ) {
 			return;
 		}
 
 		if ( $this->use_mysqli ) {
 			$num_fields = mysqli_num_fields( $this->result );
 			for ( $i = 0; $i < $num_fields; $i++ ) {
 				$this->col_info[ $i ] = mysqli_fetch_field( $this->result );
 			}
 		} else {
 			$num_fields = mysql_num_fields( $this->result );
 			for ( $i = 0; $i < $num_fields; $i++ ) {
 				$this->col_info[ $i ] = mysql_fetch_field( $this->result, $i );
 			}
 		}
 	}
 
 	/**
 	 * Retrieves column metadata from the last query.
 	 *
 	 * @since 0.71
 	 *
 	 * @param string $info_type  Optional. Possible values include 'name', 'table', 'def', 'max_length',
 	 *                           'not_null', 'primary_key', 'multiple_key', 'unique_key', 'numeric',
 	 *                           'blob', 'type', 'unsigned', 'zerofill'. Default 'name'.
 	 * @param int    $col_offset Optional. 0: col name. 1: which table the col's in. 2: col's max length.
 	 *                           3: if the col is numeric. 4: col's type. Default -1.
 	 * @return mixed Column results.
 	 */
 	public function get_col_info( $info_type = 'name', $col_offset = -1 ) {
 		$this->load_col_info();
 
 		if ( $this->col_info ) {
 			if ( -1 === $col_offset ) {
 				$i         = 0;
 				$new_array = array();
 				foreach ( (array) $this->col_info as $col ) {
 					$new_array[ $i ] = $col->{$info_type};
 					$i++;
 				}
 				return $new_array;
 			} else {
 				return $this->col_info[ $col_offset ]->{$info_type};
 			}
 		}
 	}
 
 	/**
 	 * Starts the timer, for debugging purposes.
 	 *
 	 * @since 1.5.0
 	 *
 	 * @return true
 	 */
 	public function timer_start() {
 		$this->time_start = microtime( true );
 		return true;
 	}
 
 	/**
 	 * Stops the debugging timer.
 	 *
 	 * @since 1.5.0
 	 *
 	 * @return float Total time spent on the query, in seconds.
 	 */
 	public function timer_stop() {
 		return ( microtime( true ) - $this->time_start );
 	}
 
 	/**
 	 * Wraps errors in a nice header and footer and dies.
 	 *
 	 * Will not die if wpdb::$show_errors is false.
 	 *
 	 * @since 1.5.0
 	 *
 	 * @param string $message    The error message.
 	 * @param string $error_code Optional. A computer-readable string to identify the error.
 	 *                           Default '500'.
 	 * @return void|false Void if the showing of errors is enabled, false if disabled.
 	 */
 	public function bail( $message, $error_code = '500' ) {
 		if ( $this->show_errors ) {
 			$error = '';
 
 			if ( $this->use_mysqli ) {
 				if ( $this->dbh instanceof mysqli ) {
 					$error = mysqli_error( $this->dbh );
 				} elseif ( mysqli_connect_errno() ) {
 					$error = mysqli_connect_error();
 				}
 			} else {
 				if ( is_resource( $this->dbh ) ) {
 					$error = mysql_error( $this->dbh );
 				} else {
 					$error = mysql_error();
 				}
 			}
 
 			if ( $error ) {
 				$message = '<p><code>' . $error . "</code></p>\n" . $message;
 			}
 
 			wp_die( $message );
 		} else {
 			if ( class_exists( 'WP_Error', false ) ) {
 				$this->error = new WP_Error( $error_code, $message );
 			} else {
 				$this->error = $message;
 			}
 
 			return false;
 		}
 	}
 
 
 	/**
 	 * Closes the current database connection.
 	 *
 	 * @since 4.5.0
 	 *
 	 * @return bool True if the connection was successfully closed,
 	 *              false if it wasn't, or if the connection doesn't exist.
 	 */
 	public function close() {
 		if ( ! $this->dbh ) {
 			return false;
 		}
 
 		if ( $this->use_mysqli ) {
 			$closed = mysqli_close( $this->dbh );
 		} else {
 			$closed = mysql_close( $this->dbh );
 		}
 
 		if ( $closed ) {
 			$this->dbh           = null;
 			$this->ready         = false;
 			$this->has_connected = false;
 		}
 
 		return $closed;
 	}
 
 	/**
 	 * Determines whether MySQL database is at least the required minimum version.
 	 *
 	 * @since 2.5.0
 	 *
 	 * @global string $wp_version             The WordPress version string.
 	 * @global string $required_mysql_version The required MySQL version string.
 	 * @return void|WP_Error
 	 */
 	public function check_database_version() {
 		global $wp_version, $required_mysql_version;
 		// Make sure the server has the required MySQL version.
 		if ( version_compare( $this->db_version(), $required_mysql_version, '<' ) ) {
 			/* translators: 1: WordPress version number, 2: Minimum required MySQL version number. */
 			return new WP_Error( 'database_version', sprintf( __( '<strong>Error</strong>: WordPress %1$s requires MySQL %2$s or higher' ), $wp_version, $required_mysql_version ) );
 		}
 	}
 
 	/**
 	 * Determines whether the database supports collation.
 	 *
 	 * Called when WordPress is generating the table scheme.
 	 *
 	 * Use `wpdb::has_cap( 'collation' )`.
 	 *
 	 * @since 2.5.0
 	 * @deprecated 3.5.0 Use wpdb::has_cap()
 	 *
 	 * @return bool True if collation is supported, false if not.
 	 */
 	public function supports_collation() {
 		_deprecated_function( __FUNCTION__, '3.5.0', 'wpdb::has_cap( \'collation\' )' );
 		return $this->has_cap( 'collation' );
 	}
 
 	/**
 	 * Retrieves the database character collate.
 	 *
 	 * @since 3.5.0
 	 *
 	 * @return string The database character collate.
 	 */
 	public function get_charset_collate() {
 		$charset_collate = '';
 
 		if ( ! empty( $this->charset ) ) {
 			$charset_collate = "DEFAULT CHARACTER SET $this->charset";
 		}
 		if ( ! empty( $this->collate ) ) {
 			$charset_collate .= " COLLATE $this->collate";
 		}
 
 		return $charset_collate;
 	}
 
 	/**
 	 * Determines if a database supports a particular feature.
 	 *
 	 * @since 2.7.0
 	 * @since 4.1.0 Added support for the 'utf8mb4' feature.
 	 * @since 4.6.0 Added support for the 'utf8mb4_520' feature.
 	 *
 	 * @see wpdb::db_version()
 	 *
 	 * @param string $db_cap The feature to check for. Accepts 'collation', 'group_concat',
 	 *                       'subqueries', 'set_charset', 'utf8mb4', or 'utf8mb4_520'.
 	 * @return int|false Whether the database feature is supported, false otherwise.
 	 */
 	public function has_cap( $db_cap ) {
 		$version = $this->db_version();
 
 		switch ( strtolower( $db_cap ) ) {
 			case 'collation':    // @since 2.5.0
 			case 'group_concat': // @since 2.7.0
 			case 'subqueries':   // @since 2.7.0
 				return version_compare( $version, '4.1', '>=' );
 			case 'set_charset':
 				return version_compare( $version, '5.0.7', '>=' );
 			case 'utf8mb4':      // @since 4.1.0
 				if ( version_compare( $version, '5.5.3', '<' ) ) {
 					return false;
 				}
 				if ( $this->use_mysqli ) {
 					$client_version = mysqli_get_client_info();
 				} else {
 					$client_version = mysql_get_client_info();
 				}
 
 				/*
 				 * libmysql has supported utf8mb4 since 5.5.3, same as the MySQL server.
 				 * mysqlnd has supported utf8mb4 since 5.0.9.
 				 */
 				if ( false !== strpos( $client_version, 'mysqlnd' ) ) {
 					$client_version = preg_replace( '/^\D+([\d.]+).*/', '$1', $client_version );
 					return version_compare( $client_version, '5.0.9', '>=' );
 				} else {
 					return version_compare( $client_version, '5.5.3', '>=' );
 				}
 			case 'utf8mb4_520': // @since 4.6.0
 				return version_compare( $version, '5.6', '>=' );
 		}
 
 		return false;
 	}
 
 	/**
 	 * Retrieves a comma-separated list of the names of the functions that called wpdb.
 	 *
 	 * @since 2.5.0
 	 *
 	 * @return string Comma-separated list of the calling functions.
 	 */
 	public function get_caller() {
 		return wp_debug_backtrace_summary( __CLASS__ );
 	}
 
 	/**
 	 * Retrieves the MySQL server version.
 	 *
 	 * @since 2.7.0
 	 *
 	 * @return string|null Version number on success, null on failure.
 	 */
 	public function db_version() {
 		return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
 	}
 
 	/**
 	 * Retrieves full MySQL server information.
 	 *
 	 * @since 5.5.0
 	 *
 	 * @return string|false Server info on success, false on failure.
 	 */
 	public function db_server_info() {
 		if ( $this->use_mysqli ) {
 			$server_info = mysqli_get_server_info( $this->dbh );
 		} else {
 			$server_info = mysql_get_server_info( $this->dbh );
 		}
 
 		return $server_info;
 	}
 }