get_metadata_by_mid

函数
get_metadata_by_mid ( $meta_type, $meta_id )
参数
  • (string) $meta_type Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.
    Required:
  • (int) $meta_id ID for a specific meta row.
    Required:
返回值
  • (stdClass|false) { Metadata object, or boolean `false` if the metadata doesn't exist. @type string $meta_key The meta key. @type mixed $meta_value The unserialized meta value. @type string $meta_id Optional. The meta ID when the meta type is any value except 'user'. @type string $umeta_id Optional. The meta ID when the meta type is 'user'. @type string $post_id Optional. The object ID when the meta type is 'post'. @type string $comment_id Optional. The object ID when the meta type is 'comment'. @type string $term_id Optional. The object ID when the meta type is 'term'. @type string $user_id Optional. The object ID when the meta type is 'user'. }
定义位置
相关方法
delete_metadata_by_midupdate_metadata_by_midget_metadataget_post_meta_by_idget_metadata_raw
引入
3.3.0
弃用
-

get_metadata_by_mid函数用于通过其元数据ID(MID)检索一个给定对象的元数据: 当元数据键未知时,这个函数可用于检索一个对象的元数据。

按元ID检索元数据。

function get_metadata_by_mid( $meta_type, $meta_id ) {
	global $wpdb;

	if ( ! $meta_type || ! is_numeric( $meta_id ) || floor( $meta_id ) != $meta_id ) {
		return false;
	}

	$meta_id = (int) $meta_id;
	if ( $meta_id <= 0 ) {
		return false;
	}

	$table = _get_meta_table( $meta_type );
	if ( ! $table ) {
		return false;
	}

	/**
	 * Short-circuits the return value when fetching a meta field by meta ID.
	 *
	 * The dynamic portion of the hook name, `$meta_type`, refers to the meta object type
	 * (post, comment, term, user, or any other type with an associated meta table).
	 * Returning a non-null value will effectively short-circuit the function.
	 *
	 * Possible hook names include:
	 *
	 *  - `get_post_metadata_by_mid`
	 *  - `get_comment_metadata_by_mid`
	 *  - `get_term_metadata_by_mid`
	 *  - `get_user_metadata_by_mid`
	 *
	 * @since 5.0.0
	 *
	 * @param stdClass|null $value   The value to return.
	 * @param int           $meta_id Meta ID.
	 */
	$check = apply_filters( "get_{$meta_type}_metadata_by_mid", null, $meta_id );
	if ( null !== $check ) {
		return $check;
	}

	$id_column = ( 'user' === $meta_type ) ? 'umeta_id' : 'meta_id';

	$meta = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $table WHERE $id_column = %d", $meta_id ) );

	if ( empty( $meta ) ) {
		return false;
	}

	if ( isset( $meta->meta_value ) ) {
		$meta->meta_value = maybe_unserialize( $meta->meta_value );
	}

	return $meta;
}

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