I am trying to find a way to flag for duplicates during data entry, and so far I have not been able to find a way of doing this successfully for a specific situation. Here's the situation:
I have a table called Link, which contains a field for urls (as well as some other fields). I also have a table called LinkCollection, which functions, as the name suggests, as a way of grouping together records in Link. The relationship between Link and LinkCollection is many-to-many, with a join table in between. Now, what I want is a function whereby I can catch duplicate urls in the records in Link attached to the same record in LinkCollection. In other words, duplicate urls are fine, as long as the records containing them are not linked to the same record in LinkCollection. I want validation to happen during data entry. Currently, the way to create Link records is via a portal, where the url field is one of several fields edited after creation of the record. It is therefore not the case of linking already filled out records, where validation could be a lot more simple.
Does anyone have a good idea of how to solve this? I have tried self-join relationships and a couple of different script-based solutions, but nothing has worked. Would appreciate any help!
(Working in Filemaker Pro Advanced 12)