Core Data Snippets

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1、CoreDataSnippetsContentsIntroduction3OrganizationofThisDocument3AccessingtheCoreDataStack4CoreDataStackArchitectures4OSX4iOS4GettingaManagedObjectContext4CreatingaNewManagedObjectContext5GettingtheManagedObjectModelandEntities6AddingaPersistentStore7Fetc

2、hingManagedObjects8BasicFetch8FetchwithSorting8FetchwithaPredicate9FetchwithaPredicateTemplate10FetchwithSortingandaPredicate11FetchingSpecificPropertyValues13FetchingDistinctValues13FetchingAttributeValuesthatSatisfyaGivenFunction14CreatingandDeletingMa

3、nagedObjects16CreatingaManagedObject16SavingaManagedObject16DeletingaManagedObject17DocumentRevisionHistory182009-07-06

4、Copyright©2009AppleInc.AllRightsReserved.2IntroductionThisdocumentcontainsprototypesforcommonly-usedsnippetsofcodethatyou’relikelytous

5、einaprogramthatusesCoreData.Insomecases(particularlyincaseswhereacodesnippetmightbeonlyoneortwolines),thedocumentprovidesguidanceratherthanexplicitcode.Thisdocumentdoesnotprovideanin-depthexplanationofthecodesnippets.You’reexpectedtobefamiliarwiththeCore

6、Dataframeworkandunderstandhowtousethesnippetsincontext.TolearnmoreaboutCoreData,readCoreDataStartingPoint.OrganizationofThisDocumentThedocumentcontainsthefollowingarticles:●“AccessingtheCoreDataStack”(page4)●“FetchingManagedObjects”(page8)●“FetchingSpeci

7、ficPropertyValues”(page13)●“CreatingandDeletingManagedObjects”(page16)2009-07-06

8、Copyright©2009AppleInc.AllRightsReserved.3AccessingtheCoreDataStackThisarticlecontainssnippetsforcreatingandaccessingpartsofthemainpiecesofinfrastructuredefinedbytheCoreData

9、framework.CoreDataStackArchitecturesHowyouaccessthepartsoftheCoreDatastackmaydependinpartontheapplicationarchitectureandplatform.OSXBroadly-speaking,inOSXtherearetwobasicapplicationarchitecturesforprogramsthatuseCoreData:●Single-coordinatorapplications.T

10、heseapplicationstypicallyhaveasingleCoreDatastack(asdefinedbyasinglepersistentstorecoordinator)managedbyasinglecontrollerobject.Theygenerallyuseasinglepersistentstoreforthewholeapplication.●Document-basedapplications.These