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# NSMergePolicyType

Constants that define merge policy types.

```
enum NSMergePolicyType
```

## Topics

### Policies

[`NSErrorMergePolicyType`](/documentation/CoreData/NSMergePolicyType/errorMergePolicyType)

The default merge policy for all managed object contexts.

[`NSMergeByPropertyStoreTrumpMergePolicyType`](/documentation/CoreData/NSMergePolicyType/mergeByPropertyStoreTrumpMergePolicyType)

A property-based merge policy that applies external changes.

[`NSMergeByPropertyObjectTrumpMergePolicyType`](/documentation/CoreData/NSMergePolicyType/mergeByPropertyObjectTrumpMergePolicyType)

A property-based merge policy that applies in-memory changes.

[`NSOverwriteMergePolicyType`](/documentation/CoreData/NSMergePolicyType/overwriteMergePolicyType)

A merge policy type that overwrites the entire stored object.

[`NSRollbackMergePolicyType`](/documentation/CoreData/NSMergePolicyType/rollbackMergePolicyType)

A merge policy that discards unsaved changes.

## Relationships

### Conforms To

[`Sendable`](/documentation/Swift/Sendable)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

[`Equatable`](/documentation/Swift/Equatable)

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Hashable`](/documentation/Swift/Hashable)

---

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