php pdo中没有引发异常

Question

I am trying to throw an exception in PHP but it does not throw. When I deliberately give password string (although I am not having a password on my localhost ) it gives this error:

SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: YES).

While it should be throwing my custom error message. Again if I deliberately write localhost as focalhost or change username from root to hoot , it does not throw my custom exception message.

<?php
try{
    $con = new PDO("mysql:host = localhost; dbname = chatdump", "root","");

    if(!$con){
        throw new Exception("There was some error connecting to database");
    }
}

catch(Exception $e){
    echo $e->getMessage();
}
?>

Answer 1

An exception stops the further execution, and therefore your condition is never executed.

But what is more important, your idea on throwing such a custom but useless error message is wrong. You should never rewrite a useful precise error message to just a vague notice.

What you should be doing is leaving your PDOException alone, and then catch it somewhere, and then handle it. It could be either a global try-catch for the whole code, or a dedicated error handler.

You should understand that there are two distinct kinds of people who needs to be informed of the error: the staff in charge of the site and site visitors. And both require completely different error messages. But you are depriving the former from the error message they need to resolve a problem with the site.

So what you should be doing

1. Do not rethrow an error exception with just a custom text
2. Catch all error exceptions either in a global try catch or a dedicated error handler
3. Log the exact error message for the site admin
4. Show a nice HTML page with your custom error message for a site user.

Recently I wrote an article on PHP error reporting which you may find interesting to read.