删除指定对象的元数据。
原型
delete_metadata( string $meta_type, int $object_id, string $meta_key, mixed $meta_value = '', bool $delete_all = false )
参数
$meta_type
(string)
(Required)
对象元数据的类型用于(例如,评论,帖子,术语或用户)。
$object_id
(int)
(Required)
对象元数据的ID用于
$meta_key
(string)
(Required)
元数据键
$meta_value
(mixed)
(Optional)
元数据价值。如果是非标量,则必须可序列化。如果指定,则仅删除具有此值的元数据条目。否则,删除具有指定meta_key的所有条目。传递null,false`或空字符串以跳过此检查。 (为了向后兼容,无法传递空字符串以删除值为空字符串的条目。)
$delete_all
(bool)
(Optional)
如果为true,则删除所有对象的匹配元数据条目,忽略指定的object_id。否则,仅删除指定object_id的匹配元数据条目。
返回值
(bool)
成功删除时为True,失败时为false。
源文件
路径:wp-includes/meta.php
<?php
...
function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
global $wpdb;
if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) && ! $delete_all ) {
return false;
}
$object_id = absint( $object_id );
if ( ! $object_id && ! $delete_all ) {
return false;
}
$table = _get_meta_table( $meta_type );
if ( ! $table ) {
return false;
}
$type_column = sanitize_key($meta_type . '_id');
$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
// expected_slashed ($meta_key)
$meta_key = wp_unslash($meta_key);
$meta_value = wp_unslash($meta_value);
/**
* Filters whether to delete metadata of a specific type.
*
* The dynamic portion of the hook, `$meta_type`, refers to the meta
* object type (comment, post, term, or user). Returning a non-null value
* will effectively short-circuit the function.
*
* @since 3.1.0
*
* @param null|bool $delete Whether to allow metadata deletion of the given type.
* @param int $object_id Object ID.
* @param string $meta_key Meta key.
* @param mixed $meta_value Meta value. Must be serializable if non-scalar.
* @param bool $delete_all Whether to delete the matching metadata entries
* for all objects, ignoring the specified $object_id.
* Default false.
*/
$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );
if ( null !== $check )
return (bool) $check;
$_meta_value = $meta_value;
$meta_value = maybe_serialize( $meta_value );
$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );
if ( !$delete_all )
$query .= $wpdb->prepare(" AND $type_column = %d", $object_id );
if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value )
$query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );
$meta_ids = $wpdb->get_col( $query );
if ( !count( $meta_ids ) )
return false;
if ( $delete_all ) {
if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value ) {
$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s AND meta_value = %s", $meta_key, $meta_value ) );
} else {
$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s", $meta_key ) );
}
}
/**
* Fires immediately before deleting metadata of a specific type.
*
* The dynamic portion of the hook, `$meta_type`, refers to the meta
* object type (comment, post, term, or user).
*
* @since 3.1.0
*
* @param array $meta_ids An array of metadata entry IDs to delete.
* @param int $object_id Object ID.
* @param string $meta_key Meta key.
* @param mixed $meta_value Meta value.
*/
do_action( "delete_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );
// Old-style action.
if ( 'post' == $meta_type ) {
/**
* Fires immediately before deleting metadata for a post.
*
* @since 2.9.0
*
* @param array $meta_ids An array of post metadata entry IDs to delete.
*/
do_action( 'delete_postmeta', $meta_ids );
}
$query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";
$count = $wpdb->query($query);
if ( !$count )
return false;
if ( $delete_all ) {
foreach ( (array) $object_ids as $o_id ) {
wp_cache_delete($o_id, $meta_type . '_meta');
}
} else {
wp_cache_delete($object_id, $meta_type . '_meta');
}
/**
* Fires immediately after deleting metadata of a specific type.
*
* The dynamic portion of the hook name, `$meta_type`, refers to the meta
* object type (comment, post, term, or user).
*
* @since 2.9.0
*
* @param array $meta_ids An array of deleted metadata entry IDs.
* @param int $object_id Object ID.
* @param string $meta_key Meta key.
* @param mixed $meta_value Meta value.
*/
do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );
// Old-style action.
if ( 'post' == $meta_type ) {
/**
* Fires immediately after deleting metadata for a post.
*
* @since 2.9.0
*
* @param array $meta_ids An array of deleted post metadata entry IDs.
*/
do_action( 'deleted_postmeta', $meta_ids );
}
return true;
}
...
?>
其他
英文文档:https://developer.wordpress.org/reference/functions/delete_metadata/