Core Data in
Modern Times
Jorge D. Ortiz-Fuentes
@jdortiz
#CoreDataMT

A Canonical
Examples
production
#CoreDataMT

Agenda
★ Background info
★ Comparisons
• Realm
• Android Content Providers
★ Concurrency in Core Data
★ Threats to Core Data
★ Protect yourself

Background Info

Core Data concepts
★ Data persistence
• Objects <-> Data
★ Relationships
• 1-1
• 1-M
• M-M
★ Store independence

Core Data
Persistent
Store
Persistent
Store
Persistent
Store Coordinator Managed Object
Model
Managed Object Context
MO MO MO MO MO

Core Data Virtues
★ Visual model
★ Seamless integration with Objective-C
★ Relationships, deletion rules, Faulting & Uniquing
★ Undo management and Change tracking
★ KVC & KVO
★ Filtering, sorting, grouping
★ Versioning and migration
★ Merge policies

FetchedResultsController
Anatomy
★ iOS only
★ Controller
• uses a fetch request
• coordinates getting data and caches
them
• notifies of changes

Bindings
★ OS X only
★ Sync UI and Coredata
★ Reduce the amount of code required

Comparisons
are odious

Realm

Realm: Pros & Cons
★ Born mobile
★ Models in code(PK)
★ Built in encryption
★ Multi-thread &
Multi-process
★ Good performance
★ No delete rules
★ No fine grained
notifications (KVO)
★ No null properties
★ No sync solutions

Android Content
Providers

Android Content
★ Content providers
• Abstract data sources
• Access to data via URI (REST style)
• It can be exported to other apps
• Thread safety via synchronized (or multi-
instance)
★ Content resolver to map authorities to providers

Concurrency in
Core Data

Background
Queue
Main
Queue
Single process approach
★ Context
• Private
• MainQueue
★ Nested contexts
• Save pushes changes to
parent (no I/O)
• Parent saves in the
background
child
MOC
pStore
parent
MOC

Good practices
★ Avoid premature optimization
★ Have a police for when to use concurrency
★ Really follow 1 & 2

Also available now
★ Batch updates (Brent Simmons’ problem)
★ Asynchronous fetching

UIManagedDocument
★ Uses the model in the bundle
★ Async I/O
★ Completion blocks after opening or saving
★ Parent is in background and autosaves
★ Also additional data

Threats to Core
Data

Threats
★ Swift
• Introspection is still half baked (@NSManaged)
• Many features of Cocoa depend on the runtime
★ Lack of multi-process capabilities
★ Apple generated doubts:
• Photos using
• Removed from Lister?

Protect yourself

– Robert C Martin (Uncle Bob)
“The database is a detail!”

Clean Architecture
View (VC) Presenter
Wireframe
Interactor Repository
Persistence
WSC

canonicalexamples.com
coupon:
COCOAHEADSNL

Thank
you!

@jdortiz
#CoreDataMT