Database Background: I work in the semiconductor industry and I am trying to track which wafers are processed with which masks. Not to delve into the technical side too much but we manufacture many different wafer types and each wafer type has it's own mask type. In addition we have thousands of each mask type. Currently I have built two databases; Database 1 tracks the mask inventory, and Database 2 tracks the wafer processing. They are relational so that in Database 2 when I enter the mask number it pulls in other relavent information about that mask. Also, when the mask number is enetered into Database 2, I am validating the mask number field against the mask inventory in Database 1 to make sure that it is a valid mask number.

Problem: When a mask number is assigned to a wafer in Database 1, I would like to validate multiple fields of data before the database allows the entry. Specifically I want to validate that it is a valid wafer number, that the mask type matches the wafer type, and that the mask be in an available state (the mask state can be either Available, Engineering Hold, or Scrapped)

I guess you want to set the validation by calculation something like:

>SmallestWaferNumber and <LargestWaferNumber and MaskType = WaferType and MaskState = "Available" or MaskState = "Engineering Hold' or MaskState = "Scrapped"

Chaeck Strict and isnert your own custom message.

You can of course use fields from the related database for the values.