Notes/Domino 6 and 7 Forum : Field validation using Stored Procedures

LEI 6.0 / Domino 6.0.2CF1 /DB2 on AS400

What is the best way to achieve the following?

I need to validate a field on a form by calling a stored procedure on DB2.

Can I use a DCR to do this? There is a procedure option when defining a DCR, but I am confused as to how to use this option.

(When I define the DCR it brings up a list of stored procedures which show the procedures and input/output parameters. I then attached this DCR to a field in a form. When does the procedure get called and how do I pass the input parameter values and access the output parameters?)

Can I use Virtual Agents to do the above?
Would I be able to pass and get back values using the following construct for a virtual agent?

REM set up doc with input/output fields

Set agent =db.GetAgent("Virtual Agent")

If agent.Run(doc.NoteID) = 0 Then
REM Retrieve return values from doc
Messagebox "Agent ran",, "Success"
Else
Messagebox "Agent did not run",, "Failure"
End If

This is the functionality I am looking for.

The user fills out a form and presses a button.
I use the data on a field and call a stored procedure. The stored procedure returns a value that tells me if the data is valid or not. If the field did not pass validation I would give the user a message and call the stored procedure again once the user enters new data.

Thanks for your time.