Why isn't PHP catching a MySQL error?

Question

I have the following code:

$db = new mysqli('localhost', 'xxx', 'xxx', 'dbname');

if($db->connect_errno > 0){
    die('Unable to connect to database [' . $db->connect_error . ']');
}

    try 
    {
       $db->begin_transaction();
       $db->query($q_insert_custom);
       $db->commit();
       $error_message = '';
    }
    catch (Exception $e) 
    {
       $db->rollback();
       $error_message = $e->getMessage()." **** LINE: ".$e->getLine();
    }

    echo $error_message;

There is a problem in $q_insert_custom in that it's trying to insert a row but a required field is missing. When you run the query in MySQL Workbench, I get an error about the query and how it's missing the field. But when I run it via PHP is doesn't get caught with exception handling and it appears as if the query ran just fine.

What am I doing wrong? How do I catch when MySQL throws an error about a query?

How could we know? Whats does `$db->query()` do? It's from `mysqli`? — Felippe Duarte, Jan 23 '18 at 20:04
Can you include the code that assigns `$db`? Are you using mysqli? — mkasberg, Jan 23 '18 at 20:06
https://stackoverflow.com/questions/14578243/turning-query-errors-to-exceptions-in-mysqli — AbraCadaver, Jan 23 '18 at 20:06
If it's from `mysqli::query`: **Returns FALSE on failure** http://php.net/manual/en/mysqli.query.php — Felippe Duarte, Jan 23 '18 at 20:07

score -1 · Answer 1 · answered Jan 23 '18 at 21:03

-1

A quick way to find MySQL error is to check if there is a message in $db->error. Then you can throw it throw new Exception($db->error);, if needed.

answered Jan 23 '18 at 21:03

Todor

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Why isn't PHP catching a MySQL error?

1 Answers1