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SPCascadeDropdowns - How to handle many-to-many parent/child relationships

Aug 28, 2014 at 5:40 PM
I am really liking SPCascadeDropdowns! But, in one case I’m having to deal with many to many relationships and was wondering about the best way to resolve that. If I can just remove the duplicate child values on the last select (3rd in this case), ignoring the parent values, that would be great! But how to do that is the question. I'm using SP MOSS 2007 multi-select lists (not required fields, but will probably be once development is done), which use those crazy dropdown types based on number of items. This library handles all of that madness, so I really want to use it! I've tried changing my data so that values don’t appear to be duplicates, but it gets kind of ugly and since the app doesn't care about the distinction between multiple parents, I'd prefer to just remove the duplicate child values. So, this is my set up (all use lookup fields for parent field) and main list uses multi-select lookup fields into these lists:
BTW: I was impressed that multi-selects worked down the chain, awesome!
1st list is simple list with parent values.
2nd list is one to many with unique parent/child values.
3rd list however can have child values that are the same for multiple (different) parent values.
This really doesn't matter to the list, it just wants the unique child values.
So, for the SP dropdown code these are not really duplicates of course because they have different parent values, but the dropdown shows only the child values, which appear to be duplicates.
Since I don't care about the parent value and just want the child value, is there a way to get all values from the candidate list and remove duplicate child values and then write it back to the candidate list, overwriting the previous values (and keeping SharePoint happy)?
This would be useful only in the last lookup in the chain, I imagine, as changes to mid-level lists would cascade down the chain creating havoc!...
Sep 6, 2014 at 6:26 PM
I've sort of lost you in your description. In any case, the relationshipLists can only contain one relationship per value.

Did you look at the matchOnId option?