insert into database and prevent duplicate entry

Question

So I'm trying to input records into a database. Everything inserts fine, but how do I check/make sure that I am not inserting the same information into the database. I tried the following code, but it always inserts the info no matter if its the same or not. How can I can check and stop duplicate entries?

try {
    $link = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbusername, $dbpassword);
    $link->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $query = "INSERT INTO `users`(`name`, `username`, `avatar`) VALUES (:name, :username, :avatar)";
    $statement = $link->prepare($query);
    $statement->execute(array(
        ':name' => $_POST['name'],
        ':username' => $_POST['username'],
        ':avatar' => $_POST['avatar']
    ));

    echo 'added!';
} catch(PDOException $e) {
    if ($e->errorInfo[1] == 1062) {
        // duplicate entry, do something else
        echo 'this user has already been added';
    } else {
        // an error other than duplicate entry occurred
        echo "Exception caught: $e";
    }
}

Possible duplicate: http://stackoverflow.com/questions/2219786/best-way-to-avoid-duplicate-entry-into-mysql-database — Nick, Jun 06 '14 at 22:54
To prevent duplicates in DB, modify your column(s) as `UNIQUE`. To check for duplicates, use `rowCount()` — Funk Forty Niner, Jun 06 '14 at 22:54
You can add UNIQUE constrain to your username column of USERS table, then it is possible to restrict duplicate entry — A l w a y s S u n n y, Jun 07 '14 at 00:20

score 1 · Answer 1 · answered Jun 06 '14 at 23:00

1

i am assuming that is the username that you don't want to duplicate, so you can check on you DB table on the row 'username' as UNIQUE.

hope it helped

answered Jun 06 '14 at 23:00

Denis Nagy

54
4

insert into database and prevent duplicate entry

1 Answers1