Validation on cancellation of a document

Hi,

We have a workflow where Goods Issue is always followed by Goods Receipt, for a particular scenario (the details of which are irrelevant here).

i.e. a Goods Receipt always has an associated Goods Issue document.

Whichever Goods Issue do not have associated Goods Receipt documents will show up in a Pending Goods Issue Report.

The problem is:

If the user creates a Goods Issue, followed by Goods Receipt, and then cancels the Goods Issue, I am having inconsistent data.

So I want to force the user to first cancel Goods Receipt, and only then cancel the Goods Issue.

During cancellation of Goods Issue, I want to write a validation that if a Goods Receipt document exists against this Goods Issue document, then it can not be cancelled.

How can I write this?

Is the Stored Procedure triggered during cancellation?

Thanks.