@interface RLMMigration : NSObject
RLMMigration instances encapsulate information intended to facilitate a schema migration.
RLMMigration instance is passed into a user-defined
RLMMigrationBlock block when updating
the version of a Realm. This instance provides access to the old and new database schemas, the
objects in the Realm, and provides functionality for modifying the Realm during the migration.
Enumerates all the objects of a given type in the Realm, providing both the old and new versions of each object. Within the block, object properties can only be accessed using keyed subscripting.
All objects returned are of a type specific to the current migration and should not be cast to
className. Instead, treat them as
RLMObjects and use keyed subscripting to access properties.
- (void)enumerateObjects:(nonnull NSString *)className block:(nonnull RLMObjectMigrationBlock)block;
The name of the
RLMObjectclass to enumerate.
Creates and returns an
RLMObjectinstance of type
classNamein the Realm being migrated.
valueargument is used to populate the object. It can be a key-value coding compliant object, an array or dictionary returned from the methods in
NSJSONSerialization, or an array containing one element for each managed property. An exception will be thrown if any required properties are not present and those properties were not defined with default values.
When passing in an
valueargument, all properties must be present, valid and in the same order as the properties defined in the model.
- (nonnull RLMObject *)createObject:(nonnull NSString *)className withValue:(nonnull id)value;
func createObject(_ className: String, withValue value: Any) -> RLMObject
The name of the
RLMObjectclass to create.
The value used to populate the object.
Deletes an object from a Realm during a migration.
It is permitted to call this method from within the block passed to
- (void)deleteObject:(nonnull RLMObject *)object;
func delete(_ object: RLMObject)
Object to be deleted from the Realm being migrated.
Deletes the data for the class with the given name.
All objects of the given class will be deleted. If the
RLMObjectsubclass no longer exists in your program, any remaining metadata for the class will be removed from the Realm file.
- (BOOL)deleteDataForClassName:(nonnull NSString *)name;
func deleteData(forClassName name: String) -> Bool
The name of the
RLMObjectclass to delete.
A Boolean value indicating whether there was any data to delete.
Renames a property of the given class from
- (void)renamePropertyForClass:(nonnull NSString *)className oldName:(nonnull NSString *)oldName newName:(nonnull NSString *)newName;
func renameProperty(forClass className: String, oldName: String, newName: String)
The name of the class whose property should be renamed. This class must be present in both the old and new Realm schemas.
The old name for the property to be renamed. There must not be a property with this name in the class as defined by the new Realm schema.
The new name for the property to be renamed. There must not be a property with this name in the class as defined by the old Realm schema.