The document discusses Core Data changes in iOS 10, outlining its function as a framework for managing model layer objects rather than a traditional database. Key updates include persistent containers, query generations that enable better data snapshot handling, and concurrency improvements that enhance performance by allowing multiple threads to access data without locking. It also details the structure of the Core Data stack including the managed object model, persistent store coordinator, and managed object contexts.

1. Core Data
Changes in iOS10
G. Abhisek

2. • Core Data Concepts.
• Changes in Core Data.
Contents:

3. • What is Core Data?
• Core Data Stack:
Managed Object Model
Persistent Store Coordinator
Managed Object Contexts
Core Data Concepts

4. What is Core Data?
• Its not a database.
• Its a framework - Manages model layer objects in
application.
• Three types of files are generated when core data for an
application is enabled :
- .sqlite (Database file)
- .sqlite-shm (Shared Memory)
- .sqlite-wal (Write ahead log)

5. Core Data Stack
• Managed Object Model - Data model of application.
• Persistent Store Co-ordinator - The one which persists
our data in the database.
• Managed Object Context - Collection of model objects.

7. Core Data Changes
• Persistent Containers
• Query Generations
• Concurrency Improvements

8. Persistent Containers
• It creates a managed object model, and a managed object
context.
• Provides several properties and methods to interact with
the Core Data stack.
• Provides a description about the persistent store, its
configuration, and whether it is a read-only persistent
store.

9. • Initialise Persistent Store Container:
let persistentContainer = NSPersistentContainer(name: "MyApplication")
• Get the description of Persistent store:
let persistentStoreDescription = NSPersistentStoreDescription(url: url)
• Add Persistent Store to Persistent Store Coordinator

10. Faulting
• When we fetch any entity from from Core Data database,
we are returned back with not a fully initialised managed
object, if its not required, rather it returns a kind of
placeholder for the particular managed object’s instance.
• When faults are inaccessible or faults are not fulfilled, we
encounter an exception (crash in iOS8 & exception iOS9)
• Resolve this issue by:
Setting shouldDeleteInaccessibleFaults to proper value.

11. Query Generations
• As of iOS 10 & 10.2, assigns a query generation to a
managed object context.
• It means it interacts with a snapshot of the data stored in
the persistent store.
• Any changes in the data base won’t affect the snapshot
thereby avoiding a possible case of faults.

12. Concurrency Improvements
• Earlier to iOS10, Persistent Stores locked themselves if
different contexts accessed them from different threads,
which results in performance issues, and slower Core
Data procedures.
• As of iOS 10, the persistent store is not allowed to lock
itself away, and the query is directly moved to the SQLite
database.

13. Thank You