In MySQLi, convert query errors into exceptions

Question

I'm trying to convert MySQLi query errors into exceptions, but it's not possible - the mysqli_sql_exception exception is only thrown when connecting to the database fails.

I used mysqli_report(MYSQLI_REPORT_STRICT) with a procedural MySQLi function embedded in a custom wrapper class.

Previous code:

public function mysqlQuery($SQL) {

    $this->Result = mysqli_query($this->DBlink, $SQL);

    if($this->Result === false)
        throw new MySQLiQueryException($SQL, mysqli_error($this->DBlink), mysqli_errno($this->DBlink));

    return $this->Result;

}

Question: No warning or exception is thrown when a query fails, is this normal? So I have to check if mysqli_query() returns false?

Answer 1

No.

You should be able to follow your requirements and instruct the mysqli driver to throw an exception on SQL errors, but you will need to enable MYSQLI_REPORT_ERROR if it is not already enabled....

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT)

mysqli_query() Should now throw an exception on error. You don't need to check the return value on failure (the exception will be thrown anyway).

public function mysqlQuery($SQL) {
    try {
        $this->Result = mysqli_query($this->DBlink, $SQL);
    } catch (mysqli_sql_exception $e) {
        throw new MySQLiQueryException($SQL, $e->getMessage(), $e->getCode());
    }
    return $this->Result;
}

(Note: I changed $this->SQL to $SQL in the rethrown exception.)

Answer 2

Some time ago I successfully solved this problem. As pointed out in other answers,

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

is the correct way to tell mysqli to throw an exception.

Just make sure not to wrap try-catch in every query. This is a very common misconception, once you start using exceptions you should start throwing try and catch everywhere. In contrast, try-catch should be used with caution. Although 99% of errors should not be handled on site but by a site-wide error handler. You can learn more about this topic from my PHP Error Reporting article.