constrain by data in another table

[Bruce A]

I have a geological database which needs to have 3D validation rules applied
to new data entries. Primary key is 'hole ID' for collar and geology tables.
I need to constrain geology hole depth entries to be always less than the
total hole depth as entered in the collar table.

 

[Jeff Boyce]

Bruce

You've posted in the tablesdbdesign newsgroup. In Access/JET, you don't
have triggers (as you do if you are using SQL-Server or other more robust
back-ends). You'd need a trigger to do what you've asked for directly
within tables.

But tables only hold data, where forms display it and allow for data entry.
I can easily imagine using a form for data entry that conducts the
validation check you asked about.