wpdb::has_cap( string $db_cap ): bool
Determines whether the database or WPDB supports a particular feature.
Contents
Description
Capability sniffs for the database server and current version of WPDB.
Database sniffs are based on the version of MySQL the site is using.
WPDB sniffs are added as new features are introduced to allow theme and plugin developers to determine feature support. This is to account for drop-ins which may introduce feature support at a different time to WordPress.
See also
Parameters
-
$db_cap
string Required -
The feature to check for. Accepts
'collation'
,'group_concat'
,'subqueries'
,'set_charset'
,'utf8mb4'
,'utf8mb4_520'
, or'identifier_placeholders'
.
Return
bool True when the database feature is supported, false otherwise.
Source
File: wp-includes/class-wpdb.php
.
View all references
public function has_cap( $db_cap ) {
$db_version = $this->db_version();
$db_server_info = $this->db_server_info();
// Account for MariaDB version being prefixed with '5.5.5-' on older PHP versions.
if ( '5.5.5' === $db_version && str_contains( $db_server_info, 'MariaDB' )
&& PHP_VERSION_ID < 80016 // PHP 8.0.15 or older.
) {
// Strip the '5.5.5-' prefix and set the version to the correct value.
$db_server_info = preg_replace( '/^5\.5\.5-(.*)/', '$1', $db_server_info );
$db_version = preg_replace( '/[^0-9.].*/', '', $db_server_info );
}
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( $db_version, '4.1', '>=' );
case 'set_charset':
return version_compare( $db_version, '5.0.7', '>=' );
case 'utf8mb4': // @since 4.1.0
if ( version_compare( $db_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( $db_version, '5.6', '>=' );
case 'identifier_placeholders': // @since 6.2.0
/*
* As of WordPress 6.2, wpdb::prepare() supports identifiers via '%i',
* e.g. table/field names.
*/
return true;
}
return false;
}
Changelog
Version | Description |
---|---|
6.2.0 | Added support for the 'identifier_placeholders' feature. |
4.6.0 | Added support for the 'utf8mb4_520' feature. |
4.1.0 | Added support for the 'utf8mb4' feature. |
2.7.0 | Introduced. |