Error tracking mechanism in php

Hello Friends,
I am having php services which is having lots of queries and lots of conditions. I want to track errors using some error tracking mechanism. What is the best way of tracking error in php?

For example if there is error in 100th query then it will give me exact location where this error comes from.

Please help me. Thanks in advance.

 

Check this http://nl2.php.net/manual/en/function.set-error-handler.php