What is a NSFetchedResultsController?

What is a NSFetchedResultsController?

A controller that you use to manage the results of a Core Data fetch request and to display data to the user.

What is fetched property in Core Data?

Fetched Properties in Core Data are properties that return an array value from a predicate. A fetched property predicate is a Core Data query that evaluates to an array of results.

What is Sectionnamekeypath?

The key path of the attribute that determines which section the fetched entity belongs to. iOS 3.0+

What is NSManagedObjectContext?

An object space to manipulate and track changes to managed objects. iOS 3.0+

What is core data stack in iOS?

Overview. Core Data provides a set of classes that collaboratively support your app’s model layer: An instance of NSManagedObjectModel describes your app’s types, including their properties and relationships. An instance of NSManagedObjectContext tracks changes to instances of your app’s types.

What is transformable in Core Data?

Core Data supports entity attributes of ‘Transformable’ type. Transformable type allows us to store custom data types as an object of the declared attribute for a record of an Entity. The only requirement is that our custom type should conform to NSCoding or we need to provide a custom value transformer.

What is inverse relationship in Core Data?

Inverse relationships enable Core Data to propagate change in both directions when an instance of either the source or destination type changes. Every relationship must have an inverse. When creating relationships in the Graph editor, you add inverse relationships between entities in a single step.

How do I set up NSManagedObject?

From the Xcode menu bar, choose Editor > Create NSManagedObject Subclass. Select your data model, then the appropriate entity, and choose where to save the files. Xcode places both a class and a properties file into your project.

What is the purpose of NSManagedObjectContext?

An object space to manipulate and track changes to managed objects.

What is NSManagedObjectContext in Core Data?

NSManagedObjectContext. The NSManagedObjectContext object manages a collection of model objects, instances of the NSManagedObject class. It is possible for an application to have multiple managed object contexts. Each managed object context is backed by a persistent store coordinator.

How is nsfetchedresultscontroller initialized in a view controller?

When you use Core Data with a UITableView-based layout, the NSFetchedResultsController for your data is typically initialized by the UITableViewController instance that will utilize that data. This initialization can take place in the viewDidLoad or viewWillAppear: methods, or at another logical point in the life cycle of the view controller.

Do you need a sort descriptor for nsfetchedresultscontroller?

NSFetchedResultsController requires at least one sort descriptor to control the order of the data that is being presented. After the fetch request is initialized, you can initialize the NSFetchedResultsController instance.

Which is delegate to the fetched results controller?

Typically, the table view controller is also the delegate to the fetched results controller so that it can receive callbacks whenever there are changes to the underlying data. Next, you start the NSFetchedResultsController by a call to performFetch:.

How does the fetched results controller work in Excel?

The fetched results controller uses this initial sort controller to break apart the data into multiple sections and therefore requires that the keys match. This change causes the fetched results controller to break the returning Person instances into multiple sections based on the name of the department that each Person instance is associated with.