Why won't a line of code work with error suppressor removed?

I am using PHP classes to connect to a data base. I am unable to solve a problem -- please help me out regarding this.

I have a function:

function getCampus($cm_id) //returns campus name
{
    $this->query = "select cm_name from campus where cm_id = ".$cm_id.";";
    $rd = $this->executeQuery();
    @$data = $rd->fetch_assoc();
}

and when I remove @ from @$data, it doesn't work. Please help me out: explain what i开发者_StackOverflow社区t is what an alternative way would be. Thanks.

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@ is the error suppressor operator. Using it to prefix a line of code will suppress all non fatal errors. It is a bad idea to use it nearly every time.

If you get no output with it removed, try adding error_reporting(E_ALL) in the top of your file or in a bootstrap type file and ensure display_errors = On in php.ini (you can also use ini_set('display_errors', 'on')).

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@ is used to suppress errors and warnings.

the @ is not your problem

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The @ symbol in front of commands is used to ignore any errors that happen during the execution.

That line of code still fails when you put a @ in front of it, but you don't see it. Try to figure out what the problem with $rd->fetch_assoc() is. Also, the query looks rather wrong.

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The @ when used in a PHP expression suppresses errors for that expression. So, chances are "it's not working" because $rd->fetch_assoc() is throwing an exception.