如何使用php / pdo从MySQL数据库中删除友谊并检查它是否成功

Question

Im trying to delete a friendship between two users from the db

the friendship table is simple:

friend_one |friend_two
100        |142
142        |100

Here is the code I have, but its not working:

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;
}

First of all I dont think the way I check for success is correct, second of all, the friendship doesnt get removed from the DB anyway.

When I run this I find myself in the else statement:

    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

You have an SQL error for your DELETE statement

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

You had an asterisk after delete, where there shouldn't be one. https://dev.mysql.com/doc/refman/5.0/en/delete.html

As for checking for PDO Errors, you shouldn't use $sth->rowCount().

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

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