You can use a global field to enter nay new data, lets say zgn_ID to enter the id number and check existing data of ID_No field by using self relationship with matching field as zgn_ID to ID_No.
Then you can add an onobjectsave script trigger to that globalfield.
Script can be like:
GTRR with match all records in the found set.
if getlast error is 101
create new record
set field Target:ID_No calculated:zgt_ID
show custom dialog this record already exists in db.
Hope it might help.Thanks
FileMaker 11 Certified Developer
I recommend that using GTRR like that be with the "match current record" option.
If you want to do a name based search, you have to consider the possibility that students may have the same or very similar names as well as the fact that a person's name can take many forms. (I answer to both Phil and Phillip....)
A search portal that does partial text matching and displays those records with data from other fields to help the user distinguish one matching record from another may be useful to you:
Thanks for the suggestions,
I will be trying them out.