CoreData: migration from 2 models

I have general app model, after was released any body can do plug-in for it, this plug-in can determine new db parts which merged with my general db. After some time i 'll release new db version^ and plug-in writers开发者_运维技巧 may release new version of their dbs. So i need map old version of merged db into new version. How i can do this?

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You need to review the migration documentation in Core Data. Core Data has migration built into it and you can either do light-weight automatic migration or you can create a mapping model for more complex situations.

http://developer.apple.com/mac/library/documentation/cocoa/conceptual/CoreDataVersioning/Introduction/Introduction.html