# NSStagedMigrationManager An object that handles the migration event loop and provides access to the migrating persistent store. ``` class NSStagedMigrationManager ``` ## Overview A staged migration manager contains the individual stages of a migration and applies those stages, in the order you specify, when that migration runs. The manager handles the migration’s event loop, and provides access to the migrating store through its [`container`](/documentation/CoreData/NSStagedMigrationManager/container) property. Stages can be custom, which enables you to perform tasks immediately before and after a stage runs, or lightweight, which supplements custom stages with those that Core Data can invoke automatically because they’re already compatible with lightweight migrations. Use [`NSPersistentStoreStagedMigrationManagerOptionKey`](/documentation/CoreData/NSPersistentStoreStagedMigrationManagerOptionKey) to include an instance of [`NSStagedMigrationManager`](/documentation/CoreData/NSStagedMigrationManager) in your persistent store’s options dictionary, as the following example shows: ```swift // Create a migration manager with the required stages. let manager = NSStagedMigrationManager(stages) let options = [ // Enable lightweight migrations for this store. NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true // Specify the migration manager to use with this store. NSPersistentStoreStagedMigrationManagerOptionKey: manager ] // Add the store to the persistent store coordinator. let store = coordinator.addPersistentStore( type: .sqlite, at: storeURL, options: options ) ``` ## Topics ### Creating a migration manager [`init(_:)`](/documentation/CoreData/NSStagedMigrationManager/init(_:)) Creates a migration manager with the specified stages. [`- initWithMigrationStages:`](/documentation/CoreData/NSStagedMigrationManager/initWithMigrationStages:) Creates a migration manager with the specified stages. ### Accessing the persistent container [`container`](/documentation/CoreData/NSStagedMigrationManager/container) The container that provides access to the migrating persistent store. ### Accessing the stages [`stages`](/documentation/CoreData/NSStagedMigrationManager/stages) The migration stages. ## Relationships ### Conforms To [`Equatable`](/documentation/Swift/Equatable) [`Hashable`](/documentation/Swift/Hashable) [`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol) [`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible) [`CVarArg`](/documentation/Swift/CVarArg) [`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible) ### Inherits From [`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)