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# init(from:forSourceModel:destinationModel:)

Returns the mapping model that will translate data from the source to the destination model.

```
init?(from bundles: [Bundle]?, forSourceModel sourceModel: NSManagedObjectModel?, destinationModel: NSManagedObjectModel?)
```

## Parameters

`bundles`

An array of bundles in which to search for mapping models.

`sourceModel`

The managed object model for the source store.

`destinationModel`

The managed object model for the destination store.

## Return Value

Returns the mapping model to translate data from `sourceModel` to `destinationModel`. If a suitable mapping model cannot be found, returns `nil`.

## Discussion

This method is a companion to the [`mergedModel(from:)`](/documentation/CoreData/NSManagedObjectModel/mergedModel(from:)) and [`mergedModel(from:forStoreMetadata:)`](/documentation/CoreData/NSManagedObjectModel/mergedModel(from:forStoreMetadata:)) methods. In this case, the framework uses the version information from the models to locate the appropriate mapping model in the available bundles.

## See Also

  [Core Data Model Versioning and Data Migration Programming Guide](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/Introduction.html#//apple_ref/doc/uid/TP40004399)


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