php - 如何使用 php/pdo 从 MySQL 数据库删除友谊并检查是否成功

Question

我正在尝试从数据库中删除两个用户之间的友谊

友谊表很简单:

friend_one |friend_two
100        |142
142        |100

这是我的代码，但它不起作用:

if (!empty($_POST)) {

    $remover_id      = $_POST['remover_id'];
    $removed_id      = $_POST['removed_id'];

    try {

        $query = "DELETE * FROM 

                 `friendships` 

                 WHERE 

                 (friend_one = :remover_id AND friend_two = :removed_id)

                 OR 

                 (friend_two = :remover_id AND friend_one = :removed_id)

                 ";

        $sth = $connection->prepare($query);

        $sth->execute(
                      array(

                            ':remover_id' => $remover_id,
                            ':removed_id' => $removed_id

                            ));   

        if($sth->rowCount () >=0){
            $response["success"] = $http_response_success;
            die(json_encode($response));
            $connection = null; 
        } else {
            $response["success"] = $http_response_server_error;
            $response["message"] = $http_message_server_error;   
            die(json_encode($response));
            $connection = null;
        }

    } catch (PDOException $ex) {

        $response["success"] = $http_response_server_error;
        $response["message"] = $http_message_server_error;
        die(json_encode($response));
        $connection = null;

    }  


} else {
        $response["success"] = $http_response_bad_request;
        $response["message"] = $http_message_bad_request;   
        die(json_encode($response));
        $connection = null;
}

首先，我认为我检查成功的方式不正确，其次，无论如何，友谊都不会从数据库中删除。

当我运行这个时，我发现自己处于 else 语句中:

    if($sth->rowCount () >=0){
        $response["success"] = $http_response_success;
        die(json_encode($response));
        $connection = null; 
    } else {
        $response["success"] = $http_response_server_error;
        $response["message"] = $http_message_server_error;   
        die(json_encode($response));
        $connection = null;
    }

Answer 1

您的 DELETE 语句有 SQL 错误

DELETE FROM `friendships` WHERE
   (friend_one = :remover_id AND friend_two = :removed_id)
   OR 
   (friend_two = :remover_id AND friend_one = :removed_id)

在删除之后出现了一个星号，而本不应该有这个星号。 https://dev.mysql.com/doc/refman/5.0/en/delete.html

至于检查 PDO 错误，您不应使用 $sth->rowCount()。

if(!$sth->execute($data)) {
   // Error (SQL Error)
}

if($sth->rowCount() > 0) {
   // At least 1 record was updated / inserted / deleted / (Possibly Selected)
}