Mysql_error() Not Catching INSERT Error in PHP

Question

new here and really green to programming, so go easy..

I discovered I have an INSERT that is failing because of a duplicate record error. I figured it out by running the query in a MySQL console with literals, where err#1062 popped up.

What I want to understand is why mysql_error() or mysql_errno() didn't catch this error in my PHP script.

Below is a generic setup of what I've done. I have a form that submits to a php file that calls data_insert()

function data_insert($var1, $var2, $var3, $var4){

    $db = db_connect();
    $query = "INSERT INTO exampletable (id, id_2, id_3, id_4) 
            VALUES ('$var1', '$var2', '$var3', '$var4')";

    $result = $db->query($query);
        if (!$result) 
            { 
            echo ('Database Error:' . mysql_error());
            } 
        else 
            {
            echo "Data added to db";
            }
}

The DB connection:

function db_connect()
{
    $result = new MySQLi('localhost', 'root', 'root', 'dbname');
    if (!$result)
        throw new Exception('Could not connect to database server');
    else
        return $result;
}

Result I'm getting is:

Database Error:

PHP echos "Database Error:" because the INSERT fails, but no subsequent MySQL error info is echoed. Honestly, I'm not exactly sure what I'm supposed to see, but through reading some other SO questions, I've double-checked my php.ini file for error handling and E_ALL and display_errors is set appropriately (although not sure if it matters in this case).

Is there something in my logic that I'm not understanding, like the scope of the link resource mysql_error() takes?

Thanks for your help, I'm hoping this is something embarrassingly obvious.

I know the above is missing XSS and security precautions and uniform exception handling. Baby steps though. It's simplified here for discussion's sake.

Marc B · Accepted Answer · 2011-10-26 17:21:05Z

3

You're using mysqli (note the i) for your DB operations, but are calling mysql_error (no i). They're two completely different interfaces, and do not share internal states at at all. DB handles/results from one are not usable in the other.

Try mysqli_error() instead (note the I).

answered Oct 26, 2011 at 17:21

Marc B

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1 Comment

PHPeer Over a year ago

I just knew it would be something basic. Thanks!

Niet the Dark Absol · Accepted Answer · 2011-10-26 17:22:07Z

0

As far as I can tell, you appear to be using the MySQLi class for connecting and queries, but you're trying to access MySQL error message. MySQLi and MySQL aren't the same, so errors in one will not show in the other. You should look up error handling for MySQLi, not MySQL.

answered Oct 26, 2011 at 17:22

Niet the Dark Absol

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David Barker · Accepted Answer · 2011-10-26 17:26:31Z

0

You are confusing two seperate methods for connecting to a mySQL DB.

mysql_error() will only work on queries that are run through mysql_query().

As you are using mysqli, you must use mysqli_error()

answered Oct 26, 2011 at 17:26

David Barker

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