---
title: Merge Policies
framework: coredata
role: collectionGroup
role_heading: API Collection
path: coredata/merge-policies
---

# Merge Policies

Define standard ways to handle conflicts during a save operation.

## Overview

Overview NSErrorMergePolicy is the default policy. It is the only policy that requires action to correct any conflicts. The other policies make a save go through silently by making changes that follow rules specific to that policy.

## Topics

### Policies

- [NSErrorMergePolicy](coredata/nserrormergepolicy.md)
- [NSMergeByPropertyStoreTrumpMergePolicy](coredata/nsmergebypropertystoretrumpmergepolicy.md)
- [NSMergeByPropertyObjectTrumpMergePolicy](coredata/nsmergebypropertyobjecttrumpmergepolicy.md)
- [NSOverwriteMergePolicy](coredata/nsoverwritemergepolicy.md)
- [NSRollbackMergePolicy](coredata/nsrollbackmergepolicy.md)
- [NSMergePolicyType](coredata/nsmergepolicytype.md)

## See Also

### Defining Merge Policies

- [error](coredata/nsmergepolicy/error.md)
- [mergeByPropertyStoreTrump](coredata/nsmergepolicy/mergebypropertystoretrump.md)
- [mergeByPropertyObjectTrump](coredata/nsmergepolicy/mergebypropertyobjecttrump.md)
- [overwrite](coredata/nsmergepolicy/overwrite.md)
- [rollback](coredata/nsmergepolicy/rollback.md)