Instance Method

existingObjectWithID:error:

Returns the object for the specified ID or nil if the object does not exist.

Declaration

- (__kindof NSManagedObject *)existingObjectWithID:(NSManagedObjectID *)objectID error:(NSError * _Nullable *)error;

Parameters

objectID

The object ID for the requested object.

error

If there is a problem in retrieving the object specified by objectID, upon return contains an error that describes the problem.

Return Value

The object specified by objectID. If the object cannot be fetched, or does not exist, or cannot be faulted, it returns nil.

Discussion

If there is a managed object with the given ID already registered in the context, that object is returned directly; otherwise the corresponding object is faulted into the context.

This method might perform I/O if the data is uncached.

Unlike objectWithID:, this method never returns a fault.

See Also

Registering and Fetching Objects

- executeFetchRequest:error:

Returns an array of objects that meet the criteria specified by a given fetch request.

- countForFetchRequest:error:

Returns the number of objects a given fetch request would have returned if it had been passed to executeFetchRequest:error:.

- objectRegisteredForID:

Returns the object for a specified ID, if the object is registered with the context.

- objectWithID:

Returns an object for a specified ID even if the object needs to be fetched.

registeredObjects

The set of objects registered with the context.

- executeRequest:error:

Passes a request to the persistent store without affecting the contents of the managed object context and returns a persistent store result.

- refreshAllObjects

Refreshes all currently registered objects that are associated with this context.

retainsRegisteredObjects

A Boolean value that indicates whether the context keeps strong references to all registered managed objects.

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