Warning in core data database

I have created c开发者_开发问答ore data database in xcode. i haven't insert any thing in DB and getting following worning. DipItItemOptions has a relationship with DipItItems entity

DipItItemOptions.newRelationship1 should have an inverse

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It is recommended that relationships in Core Data work both ways. So if DipItItemOptions has a relationship with DipItItems, then DipItItems should also have a relationship with DipItItemOptions. It's not always necessary but recommended anyway.