maybe_convert_table_to_utf8mb4() │ WP 4.2.0

If a table only contains utf8 or utf8mb4 columns, convert it to utf8mb4.

No Hooks.

Return

true|false. True if the table was converted, false if it wasn't.

Usage

maybe_convert_table_to_utf8mb4( $table );
$table(string) (required)
The table to convert.

Examples

0

#1 Change the encoding of all table fields to utf8mb4 

register_activation_hook( __FILE__, 'myplugin_activate' );
function myplugin_activate() {
	$table = 'my_table';

	require ABSPATH . '/wp-admin/includes/upgrade.php';
	maybe_convert_table_to_utf8mb4( $table );
}

Notes

  • Global. wpdb. $wpdb WordPress database abstraction object.

Changelog

Since 4.2.0 Introduced.

maybe_convert_table_to_utf8mb4() code WP 6.7.2

wp-admin/includes/upgrade.php 
function maybe_convert_table_to_utf8mb4( $table ) {
	global $wpdb;

	$results = $wpdb->get_results( "SHOW FULL COLUMNS FROM `$table`" );
	if ( ! $results ) {
		return false;
	}

	foreach ( $results as $column ) {
		if ( $column->Collation ) {
			list( $charset ) = explode( '_', $column->Collation );
			$charset         = strtolower( $charset );
			if ( 'utf8' !== $charset && 'utf8mb4' !== $charset ) {
				// Don't upgrade tables that have non-utf8 columns.
				return false;
			}
		}
	}

	$table_details = $wpdb->get_row( "SHOW TABLE STATUS LIKE '$table'" );
	if ( ! $table_details ) {
		return false;
	}

	list( $table_charset ) = explode( '_', $table_details->Collation );
	$table_charset         = strtolower( $table_charset );
	if ( 'utf8mb4' === $table_charset ) {
		return true;
	}

	return $wpdb->query( "ALTER TABLE $table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci" );
}

wpdb

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