---
title: NSMergePolicyType.mergeByPropertyStoreTrumpMergePolicyType
framework: coredata
role: symbol
role_heading: Case
path: coredata/nsmergepolicytype/mergebypropertystoretrumpmergepolicytype
---

# NSMergePolicyType.mergeByPropertyStoreTrumpMergePolicyType

A property-based merge policy that applies external changes.

## Declaration

```swift
case mergeByPropertyStoreTrumpMergePolicyType
```

## Discussion

Discussion A policy that merges conflicts between the persistent store’s version of the object and the current in-memory version by individual property, with external changes trumping in-memory changes.

## See Also

### Policies

- [NSMergePolicyType.errorMergePolicyType](coredata/nsmergepolicytype/errormergepolicytype.md)
- [NSMergePolicyType.mergeByPropertyObjectTrumpMergePolicyType](coredata/nsmergepolicytype/mergebypropertyobjecttrumpmergepolicytype.md)
- [NSMergePolicyType.overwriteMergePolicyType](coredata/nsmergepolicytype/overwritemergepolicytype.md)
- [NSMergePolicyType.rollbackMergePolicyType](coredata/nsmergepolicytype/rollbackmergepolicytype.md)