确定是否为给定对象设置了元键
原型
metadata_exists( string $meta_type, int $object_id, string $meta_key )
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。
返回值
(bool)
设置密钥的真,否则为假。
源文件
路径:wp-includes/meta.php
<?php
...
function metadata_exists( $meta_type, $object_id, $meta_key ) {
if ( ! $meta_type || ! is_numeric( $object_id ) ) {
return false;
}
$object_id = absint( $object_id );
if ( ! $object_id ) {
return false;
}
/** This filter is documented in wp-includes/meta.php */
$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true );
if ( null !== $check )
return (bool) $check;
$meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' );
if ( !$meta_cache ) {
$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
$meta_cache = $meta_cache[$object_id];
}
if ( isset( $meta_cache[ $meta_key ] ) )
return true;
return false;
}
...
?>
其他
英文文档:https://developer.wordpress.org/reference/functions/metadata_exists/