Validation Rule

[bogglebeats]

I am trying to create a validation rule for a field called session number. I want to make it so a duplicate session number is not able to be selected on my form. I am trying to create the proper validation rule for this by linking it to another field called session date. i would like to do something like:

session number not = session date < current date

i know my syntax is off. can anyone suggest a proper validation rule for the session number field? cheers.

ameen

 

[WayneRyan]

bogglebeats,

I assume that the user is entering the session number.

Use the AfterUpdate event, then use the DLookUp function
to check for a duplicate.

See the Help files for info ...

hth,
Wayne

 

[bogglebeats]

do i use these functions in the 'validation rule' part of the table?

 

[WayneRyan]

ameen,

Use the AfterUpdate event on the txtBox where they enter
the date.

Wayne

 

[Rich]

You should use the BeforeUpdate event, where the update can be cancelled

 

[bogglebeats]

ok. that makes sense. so i shouldn't use afterupdate at all? should i build a macro in the beforeupdate event?