Checking an empty Core Data relationship (SQLite)

Posted by rwat on Stack Overflow See other posts from Stack Overflow or by rwat
Published on 2009-06-29T16:12:12Z Indexed on 2010/04/11 14:33 UTC
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Filed under:

cocoa-touch

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cocoa

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sqlite

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core-data

I have a to-many relationship in my data model, and I'd like to get all the objects that have no corresponding objects in the relationship. For example:

Customer -> Purchases

I want to get all Customers that have 0 Purchases.

I've read somewhere that I could use "Purchases[SIZE] = 0", but this gives me an unsupported function expression error, which I think means it doesn't work with a SQLite backing store (which I don't want to switch from, due to some performance constraints).

Any ideas?

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