我开发了一个功能，可以检查更新帖子上是否存在特定帖子元值的重复值。当用户更新数据时，如果发现任何记录，则在管理仪表板中给出错误消息（请参阅随附的屏幕截图）。您可以根据需要使用以下代码。

class Check_duplicate_entry {
  public function __construct(){
   add_action( \'save_post\', array( $this, \'save_post\' ) );
   add_action( \'admin_notices\', array( $this, \'admin_notices_callback\' ) );
  }

   public function save_post( $post_id ) {
    global $wpdb;
    $issue_id = $_POST[\'issue_magazine_id\'];
    $issue_number = $_POST[\'issue_number\'];
    $query = "SELECT $wpdb->posts.ID  FROM $wpdb->posts  INNER JOIN wp_postmeta ON ( $wpdb->posts.ID = $wpdb->postmeta.post_id )  INNER JOIN $wpdb->postmeta AS mt1 ON ( wp_posts.ID = mt1.post_id ) WHERE 1=1  AND ( 
  ( $wpdb->postmeta.meta_key = \'issue_magazine_id\' AND $wpdb->postmeta.meta_value = $issue_id ) 
  AND 
  ( mt1.meta_key = \'issue_number\' AND mt1.meta_value = $issue_number )
)";
    $result = $wpdb->get_results($query);

    if($result && $post_id != $result[0]->ID){

    // Add your query var if the coordinates are not retreive correctly.
        add_filter( \'redirect_post_location\', array( $this, \'add_notice_query_variable\' ), 99 );
    }
    else
    {
        if ( !empty( $_POST[ \'issue_magazine_id\' ] ) ) {
            update_post_meta( $post_id, \'issue_magazine_id\', $_POST[ \'issue_magazine_id\' ]);
        } else {
            delete_post_meta( $post_id, \'issue_magazine_id\' );
        }

        if ( !empty( $_POST[ \'issue_number\' ] ) ) {
            update_post_meta( $post_id, \'issue_number\', $_POST[ \'issue_number\' ]);
        } else {
            delete_post_meta( $post_id, \'issue_number\' );
        }
    }
  }

  public function add_notice_query_variable( $location ) {
   remove_filter( \'redirect_post_location\', array( $this, \'add_notice_query_variable\' ), 99 );
   return add_query_arg( array( \'issue_magazine_id\' => $_POST[\'issue_magazine_id\'],\'issue_number\' => $_POST[\'issue_number\'] ), $location );
  }

  public function admin_notices_callback() {
   if ( ! isset( $_GET[\'issue_magazine_id\'] ) && ! isset( $_GET[\'issue_number\'] ) ) {
     return;
   }
   ?>
   <div class="error notice">
      <p><?php esc_html_e( \'Issue ID : \'.$_GET[\'issue_magazine_id\'].\' and Issue Number : \'. $_GET[\'issue_number\'].\' already updated in other post, Please try different!\', \'\' ); ?></p>
   </div>
   <?php
  }
}
$Check_duplicate_entry = new Check_duplicate_entry();

非常感谢。