Tomáš Jukin@Inza

Core Datathere is an ORM you can like!

Core Data?

Core Data?

-- It’s a big hairy mess!

Core Data?

-- It’s a big hairy mess!YES! but Why?

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard.

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard. Really?

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard. Really? Really.

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard. Really? Really.CoreData is hairy

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard. Really? Really.CoreData is hairy because it ...

Core Data?

-- It’s a big hairy mess!YES! but Why?Real problems are hard. Really? Really.CoreData is hairy because it ...

... solves real problems!

Tomáš Jukin@Inza

www.juicymo.cz@JuicymoCZ

1) WHY and WHEN to use Core Data?

1) WHY and WHEN to use Core Data?

2) HOW to use Core Data?

WHY?

1) Death

1) Death2) Taxes

1) Death2) Taxes

3) SW Requirements WILL change

“Do you understand how to structure real-world data access for Mac and iOS applications better than

Apple?”

“Do you understand how to structure real-world data access for Mac and iOS applications better than

Apple?”

-- Nope.

• Handling future changes to the data schema

• Bi-directional sync with servers• Bi-directional sync with peers (e.g. iPad <-> iPhone)

• Undo - Redo• Multithreading long-running operations• Sync data between multiple threads• Notifying faraway code about changes to

objects so that they can refresh or update at appropriate intervals

Has your own so-called “data stack” features like this?

Do I need these features?(= WHEN?)

But if...

I NEVER update my app!

My users NEVER do mistakes!I NEVER use threads!

My app is just one view!

My data operations ARE all instantaneous!

Requirements of my apps NEVER changes!

1) Death2) Taxes

3) SW Requirements WILL change

... all of that is TRUE for you

Core Data is NOT for you.

... all of that is TRUE for you

Core Data is NOT for you.

Otherwise you SHOULD use it.

Core Data =

Do not implementDo not test

Do not optimize

Core Data =

Do not implementDo not test

Do not optimizeData Stack code used by your app!

Apple has already done that!

Fact

Apple’s high-level APIs can be much faster than YOUR “optimized” code at lower

levels

Fact

Example:

Fast Image? ➜ UIImageView

Fact

CoreData is

Cocoa for Models

Cocoa for Models

Is UIButton easy?Is UITableView easy?

Is Delegation Pattern easy?Is InterfaceBuilder and

outlets easy?

Cocoa for Models

Is UIButton easy?Is UITableView easy?

Is Delegation Pattern easy?Is InterfaceBuilder and

outlets easy?NOPE!

Cocoa for Models

Are they powerful?

Cocoa for Models

Are they powerful?YES!

Why NOT to use Core Data?

•Programmer naivity

•Programmer naivity➜ “My app isn’t complex enought”

= I am too lazy to learn it

Why NOT to use Core Data?

•Programmer naivity➜ “My app isn’t complex enought”

= I am too lazy to learn it➜ “I dont like large frameworks - I used them in HALF of my app and it was so much work!”

= Use entirely it or not. Otherwise it will not save time & effort

Why NOT to use Core Data?

•Programmer naivity➜ “My app isn’t complex enought”

= I am too lazy to learn it➜ “I dont like large frameworks - I used them in HALF of my app and it was so much work!”

= Use entirely it or not. Otherwise it will not save time & effort

•Willful ignorance

Why NOT to use Core Data?

•Programmer naivity➜ “My app isn’t complex enought”

= I am too lazy to learn it➜ “I dont like large frameworks - I used them in HALF of my app and it was so much work!”

= Use entirely it or not. Otherwise it will not save time & effort

•Willful ignorance➜ “I don’t have any idea what I’m talking about, but it sounds like a bad idea to me”

= What?

Why NOT to use Core Data?

So?

Reading code is hardWriting code is easyWhy learn when we can re-invent?

Really? If this works in your world,Core Data is not for you...

OK, but when seriously NO?

Update HUGE part of DB in one moment

Working with lots of records

➜ RSS Reader app

Still not ready to use Core Data?

Read this: goo.gl/Flzrsk

Numbers here: goo.gl/lNFjdr

HOW?

.sqlite

Schema

App

.sqlite

ORM Schema

App

.sqlite

App

Core Data Schema

App

.sqlite Web Store

.sqlite

App

Schema

App

.sqlite Web Store

NSManagedObjectContext

NSManagedObjectContext

NSManagedObjectModel

PersistentObjectStore

PersistentObjectStore

PersistentObjectStore

PersistentStore Coordinator

.sqlite

App

Schema

App

.sqlite Web Store

NSManagedObjectNSManaged

ObjectNSManagedObject

NSManagedObjectContext

NSManagedObjectContext

NSManagedObjectModel

PersistentObjectStore

PersistentObjectStore

PersistentObjectStore

PersistentStore Coordinator

...Complex ORM

=> Complex Setup

Setup

// In the AppDelegate.h@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator; 

- (void)saveContext;- (NSURL *)applicationDocumentsDirectory; 

// In the AppDelegate.m- (void)applicationWillTerminate:(UIApplication *)application{ // Saves changes in the application's managed object context before the application terminates. [self saveContext];} 

- (void)saveContext{ NSError *error = nil; NSManagedObjectContext *managedObjectContext = self.managedObjectContext; if (managedObjectContext != nil) { if ([managedObjectContext hasChanges] &amp;&amp; ![managedObjectContext save:&amp;error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } }} 

#pragma mark - Core Data stack 

/** Returns the managed object context for the application. If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application. */- (NSManagedObjectContext *)managedObjectContext{ if (__managedObjectContext != nil) { return __managedObjectContext; } 

NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { __managedObjectContext = [[NSManagedObjectContext alloc] init]; [__managedObjectContext setPersistentStoreCoordinator:coordinator]; } return __managedObjectContext;} 

/** Returns the managed object model for the application. If the model doesn't already exist, it is created from the application's model. */- (NSManagedObjectModel *)managedObjectModel{ if (__managedObjectModel != nil) { return __managedObjectModel; } NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"blaba" withExtension:@"momd"]; __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]; return __managedObjectModel;} 

/** Returns the persistent store coordinator for the application. If the coordinator doesn't already exist, it is created and the application's store added to it. */- (NSPersistentStoreCoordinator *)persistentStoreCoordinator{ if (__persistentStoreCoordinator != nil) { return __persistentStoreCoordinator; } 

NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"blaba.sqlite"]; 

NSError *error = nil; __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&amp;error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); }  

return __persistentStoreCoordinator;} 

#pragma mark - Application's Documents directory 

/** Returns the URL to the application's Documents directory. */- (NSURL *)applicationDocumentsDirectory{ return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];}

99 rows!

Really ?!

Core Data bites!

The Cure

1) MagicalRecord

github.com/magicalpanda/MagicalRecord

The Cure

1) MagicalRecord

github.com/magicalpanda/MagicalRecord

2) Mogenerator

github.com/rentzsch/mogenerator

The Cure

1) MagicalRecord

github.com/magicalpanda/MagicalRecord

2) Mogenerator

github.com/rentzsch/mogenerator

+ CocoaPods (as usual)

Magical Record

Magical Record

Nice (Rails like) API on Core Data

Magical Record

Nice (Rails like) API on Core Data

You still can dive in!

// In the AppDelegate.h@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator; 

- (void)saveContext;- (NSURL *)applicationDocumentsDirectory; 

// In the AppDelegate.m- (void)applicationWillTerminate:(UIApplication *)application{ // Saves changes in the application's managed object context before the application terminates. [self saveContext];} 

- (void)saveContext{ NSError *error = nil; NSManagedObjectContext *managedObjectContext = self.managedObjectContext; if (managedObjectContext != nil) { if ([managedObjectContext hasChanges] &amp;&amp; ![managedObjectContext save:&amp;error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } }} 

#pragma mark - Core Data stack 

/** Returns the managed object context for the application. If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application. */- (NSManagedObjectContext *)managedObjectContext{ if (__managedObjectContext != nil) { return __managedObjectContext; } 

NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { __managedObjectContext = [[NSManagedObjectContext alloc] init]; [__managedObjectContext setPersistentStoreCoordinator:coordinator]; } return __managedObjectContext;} 

/** Returns the managed object model for the application. If the model doesn't already exist, it is created from the application's model. */- (NSManagedObjectModel *)managedObjectModel{ if (__managedObjectModel != nil) { return __managedObjectModel; } NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"blaba" withExtension:@"momd"]; __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]; return __managedObjectModel;} 

/** Returns the persistent store coordinator for the application. If the coordinator doesn't already exist, it is created and the application's store added to it. */- (NSPersistentStoreCoordinator *)persistentStoreCoordinator{ if (__persistentStoreCoordinator != nil) { return __persistentStoreCoordinator; } 

NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"blaba.sqlite"]; 

NSError *error = nil; __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&amp;error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); }  

return __persistentStoreCoordinator;} 

#pragma mark - Application's Documents directory 

/** Returns the URL to the application's Documents directory. */- (NSURL *)applicationDocumentsDirectory{ return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];}

CD

99 rows!

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ [MagicalRecord

setupCoreDataStackWithStoreNamed:@"MyDatabase.sqlite"];

// ... return YES;} - (void)applicationWillTerminate:(UIApplication *)application{ [MagicalRecord cleanUp];}

MR

11 rows!

Fetch

NSArray  *fetchedObjects;NSManagedObjectContext  *context  =  [self  

managedObjectContext];NSFetchRequest  *fetch  =  [[NSFetchRequest  alloc]  init];NSEntityDescription  *entityDescription  =  

[NSEntityDescription  entityForName:@"Person"    inManagedObjectContext:context];

[fetch  setEntity:entityDescription];[fetch  setPredicate:[NSPredicate  

predicateWithFormat:@"age  =  %d",  25]];NSError  *error  =  nil;fetchedObjects  =  [context  

executeFetchRequest:fetch  error:&error];

if([fetchedObjects  count]  ==  1)        return  [fetchedObjects  objectAtIndex:0];else        return  nil;

CD

NSArray  *fetchedObjects;NSManagedObjectContext  *context  =  [self  

managedObjectContext];NSFetchRequest  *fetch  =  [[NSFetchRequest  alloc]  init];NSEntityDescription  *entityDescription  =  

[NSEntityDescription  entityForName:@"Person"    inManagedObjectContext:context];

[fetch  setEntity:entityDescription];[fetch  setPredicate:[NSPredicate  

predicateWithFormat:@"age  =  %d",  25]];NSError  *error  =  nil;fetchedObjects  =  [context  

executeFetchRequest:fetch  error:&error];

if([fetchedObjects  count]  ==  1)        return  [fetchedObjects  objectAtIndex:0];else        return  nil;

CD

[Person findByAttribute:@"age" withValue:@25];

MR

// Query to find all the persons store into the databaseNSArray *persons = [Person MR_findAll]; // Query to find all the persons store into the database order by their 'firstname'NSArray *personsSorted = [Person MR_findAllSortedBy:@"firstname"

ascending:YES]; // Query to find all the persons store into the database which have 25 years oldNSArray *personsWhoHave22 = [Person MR_findByAttribute:@"age"

withValue:[NSNumber numberWithInt:25]]; // Query to find the first person store into the databePerson *person = [Person MR_findFirst];

MR

// Query to find all the persons store into the databaseNSArray *persons = [Person MR_findAll]; // Query to find all the persons store into the database order by their 'firstname'NSArray *personsSorted = [Person MR_findAllSortedBy:@"firstname"

ascending:YES]; // Query to find all the persons store into the database which have 25 years oldNSArray *personsWhoHave22 = [Person MR_findByAttribute:@"age"

withValue:[NSNumber numberWithInt:25]]; // Query to find the first person store into the databePerson *person = [Person MR_findFirst];

MR

// Query to find all the persons store into the databaseNSArray *persons = [Person findAll]; // Query to find all the persons store into the database order by their 'firstname'NSArray *personsSorted = [Person findAllSortedBy:@"firstname"

ascending:YES]; // Query to find all the persons store into the database which have 25 years oldNSArray *personsWhoHave22 = [Person findByAttribute:@"age"

withValue:[NSNumber numberWithInt:25]]; // Query to find the first person store into the databePerson *person = [Person findFirst];

MR

Background Op

[MagicalRecord  saveWithBlock:^(NSManagedObjectContext  *localContext)  {        Post  *post  =  

[Post  createInContext:localContext];

       //  photo  processing        //  update  post  from  photo  processing}  completion:^(BOOL  success,  NSError  *error)  {      //  This  is  called  when  data  done,        //  and  is  called  on  the  main  thread}];

MR

Mogenerator

Mogenerator

Because Xcode sucks!

Mogenerator

Because Xcode sucks!

_User for machineUser for human

Mogenerator

Because Xcode sucks!

_User for machineUser for human

+ auto regen!

But the docs sucks too!

It coves the basics, but I DO NEED to DIVE in!

goo.gl/9fNe0z

goo.gl/durEGR

Recap

•You want to use Core Data•You want to use NSFetchResultsController•You want to use MagicalRecord•You want to use Mogenerator•YOP, setup of that is epic!•You want to use CocoaPods

•YOP, docs for CoreData and MagicalRecord sucks

LET the CoreData work for you!

For-Mobile

http://srazy.info/for-mobile

Pondělí, 24. 3. 2014  19:00

Jakub HladíkAutomatic builds for iOS

=> Tomorrow!=> AfterPUB included!

Tomáš Jukin@Inza

www.juicymo.cz@JuicymoCZ

Tomáš Jukin@Inza

www.juicymo.cz@JuicymoCZ

goo.gl/jGLovj

Photo Credits

All photos used are CC from Flickr

http://www.flickr.com/photos/60256070@N05/8330184193/