mysql_insert_id, does not return the last inserted id when i place it in a function

Question

mysql_insert_id does not return the last inserted id when i place it inside a function.

im kinda confused why it does not.

here is my code:

function addAlbum($artist,$album,$year,$genre) {
    $connection = mysql_connect(HOST,USER,PASS);
    $sql = 'INSERT INTO `'.TABLE_ARTIST.'` (artistName) VALUES ("'.$artist.'")';
    $resultArtist = mysql_query($sql);
    $sql = 'INSERT INTO `'.TABLE_ALBUMS.'` (albumName) VALUES ("'.$album.'")';
    $resultAlbums = mysql_query($sql);
    $sql = 'INSERT INTO `'.TABLE_GENRE.'` (musicGenre) VALUES ("'.$genre.'")';
    $resultGenre = mysql_query($sql);
    $sql = 'INSERT INTO `'.TABLE_YEAR.'` (albumYear) VALUES ("'.$year.'")';
    $resultYear = mysql_query($sql);
    $lastId = mysql_insert_id();
    $sql = 'INSERT INTO `'.TABLE_LINK.'` (albumsId,artistId,genreId,yearId) VALUES ("'.$lastId.'","'.$lastId.'","'.$lastId.'","'.$lastId.'")';
    $resultLink = mysql_query($sql);
    if(!$resultArtist && $resultAlbums && $resultGenre && $resultYear && $resultLink){
        echo mysql_error();    
    }
}

thanks in advance

adam

Answer 1

You are calling mysql_insert_id() once after four separate INSERTs, and using that ID four times for albumsId, artistId, genreId and yearId. That doesn't seem right.

You should also check that your tables are using AUTO_INCREMENT fields. If not, mysql_insert_id() will not return the insert ID. See the docs:

http://www.php.net/manual/en/function.mysql-insert-id.php

I highly recommend that you use prepared statements with mysqli::prepare, perhaps via PDO. It's ultimately simpler and safer. Here's an untested example:

$dsn = 'mysql:dbname=test;host=127.0.0.1';
$user = 'dbuser';
$password = 'dbpass';

$dbh = new PDO($dsn, $user, $password);

$stmt_artist = $dbh->prepare(
    'INSERT INTO `table_artist` (artistName) VALUES (?)'
);

$stmt_albums = $dbh->prepare(
    'INSERT INTO `table_albums` (albumName) VALUES (?)'
);

$stmt_genre = $dbh->prepare(
    'INSERT INTO `table_genre` (musicGenre) VALUES (?)'
);

$stmt_year = $dbh->prepare(
    'INSERT INTO `table_year` (albumYear) VALUES (?)'
);

$stmt_link = $dbh->prepare(
    'INSERT INTO `table_link` (albumsId, artistId, genreId, yearId) '.
    'VALUES (?, ?, ?, ?)'
);

$stmt_albums->execute(array( $artist ));
$artist_id = $dbh->lastInsertId();

$stmt_albums->execute(array( $album ));
$album_id = $dbh->lastInsertId();

$stmt_genre->execute(array( $genre ));
$genre_id = $dbh->lastInsertId();

$stmt_year->execute(array( $year ));
$year_id = $dbh->lastInsertId();

$stmt_link->execute(array( $artist_id, $album_id, $genre_id, $year_id ));