wpdb::get_table_charset()
Retrieves the character set for the given table.
Method of the class: wpdb{}
Hooks from the method
Return
String|WP_Error
. Table character set, WP_Error object if it couldn't be found.
Usage
// protected - for code of main (parent) or child class $result = $this->get_table_charset( $table );
- $table(string) (required)
- Table name.
Changelog
Since 4.2.0 | Introduced. |
wpdb::get_table_charset() wpdb::get table charset code WP 6.6.2
protected function get_table_charset( $table ) { $tablekey = strtolower( $table ); /** * Filters the table charset value before the DB is checked. * * Returning a non-null value from the filter will effectively short-circuit * checking the DB for the charset, returning that value instead. * * @since 4.2.0 * * @param string|WP_Error|null $charset The character set to use, WP_Error object * if it couldn't be found. 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', __( 'Could not retrieve table charset.' ) ); } 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 ); $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; }