Ios:core Data Entry

Core data is an ORM framework, much like. NET Framework of EntityFramework. The basic steps to use are:

• Introduction of Coredata.framework (Standard library) in Project properties
• Create a new Datamodel (build *.xcdatamodeld file) in your project
• Create entity in Datamodel
• Generate header file for Entity (menu Editor/create nsmangedobject subclass ...)
• Add Managedobjectcontext in the project's only delegate class (AppDelegate.h, APPDELEGATE.M) to manipulate core Data
• Code anywhere reference Managedobjectcontext read and write data

Model: (Note: mychapter, mycontent these relationships are cascade so that child objects are deleted when the parent object is removed)

Generated header file:

/*Book.h*/@interfaceBook:nsmanagedobject@property (nonatomic, retain) NSNumber*bookId, @property (nonatomic, retain) nsstring*Name: @property (nonatomic, retain) nsstring*author, @property (nonatomic, retain) nsstring*Summary, @property (nonatomic, retain) Nsset*mychapters;@end@interfaceBook (coredatageneratedaccessors)- (void) Addmychaptersobject: (Nsmanagedobject *) value;- (void) Removemychaptersobject: (Nsmanagedobject *) value;- (void) Addmychapters: (Nsset *) values;- (void) Removemychapters: (Nsset *) values;@end/*Chapter.h*/@classBook ;@interfaceChapter:nsmanagedobject@property (nonatomic, retain) NSNumber*Chapid, @property (nonatomic, retain) nsstring*Name: @property (nonatomic, retain) NSNumber*orderId, @property (nonatomic, retain) book*Ownerbook, @property (nonatomic, retain) Nsmanagedobject*mycontent;@end/*TextContent.h*/@classChapter;@interfaceTextcontent:nsmanagedobject@property (nonatomic, retain) NSNumber*Chapid, @property (nonatomic, retain) nsstring*text; @property (nonatomic, retain) Chapter*Ownerchapter;@end

Delegate Class Code

AppDelegate.h

//AppDelegate.h#import<UIKit/UIKit.h>#import<CoreData/CoreData.h>#import "Book.h"#import "Chapter.h"#import "TextContent.h"@interfaceAppdelegate:uiresponder <UIApplicationDelegate>@property (Strong, nonatomic) UIWindow*window; @property (strong, nonatomic) Nsmanagedobjectcontext*Managedobjectcontext;@end

Appdelegate.m

@implementationappdelegate@synthesizeManagedobjectcontext =_managedobjectcontext;-(Nsmanagedobjectcontext *) managedobjectcontext{if(_managedobjectcontext! =Nil) {        return_managedobjectcontext; } _managedobjectcontext=[[Nsmanagedobjectcontext alloc]init]; //Setting the database pathNsurl *url =[[[ Nsfilemanager Defaultmanager] urlsfordirectory:nsdocumentdirectory Indomains:nsuserdomainmask]la    Stobject]; Nsurl*storedatabaseurl = [url urlbyappendingpathcomponent:@"Books.sqlite"]; //Create PresistentstorecoordinatorNserror *error =Nil; Nspersistentstorecoordinator*presistentstorecoordinator =[[Nspersistentstorecoordinator alloc] Initwithmanagedobjectmodel:[nsmanagedobjectmodel mergedModelFromBundles        : nil]]; //specifying storage type and path    if(![Presistentstorecoordinator addpersistentstorewithtype:nssqlitestoretype configuration:nil URL:storeDat Abaseurl Options:nil Error:&ERROR]) {NSLog (@"Error:%@", error);    } [_managedobjectcontext Setpersistentstorecoordinator:presistentstorecoordinator]; return_managedobjectcontext;}

Using _managedobjectcontext to operate core Data

//Save New Object-(void) teststore{//get context from AppdelegateAppdelegate *appdelegate = [UIApplication sharedapplication].Delegate; Nsmanagedobjectcontext*context =[Appdelegate Managedobjectcontext]; //First chapterTextcontent *content1 = [nsentitydescription insertnewobjectforentityforname:@"textcontent"Inmanagedobjectcontext:context]; Content1.chapid= [NSNumber numberwithint: -]; Content1.text=@"Hello1"; Chapter*chapter1 = (Chapter *) [nsentitydescription insertnewobjectforentityforname:@"Chapter"Inmanagedobjectcontext:context]; Chapter1.name=@"Hello1"; Chapter1.orderid= [NSNumber numberwithint:0]; Chapter1.chapid= [NSNumber numberwithint: -]; Chapter1.mycontent=Content1; //Chapter TwoTextcontent *content2 = [nsentitydescription insertnewobjectforentityforname:@"textcontent"Inmanagedobjectcontext:context]; Content2.chapid= [NSNumber numberwithint: -]; Content2.text=@"Hello2"; Chapter*chapter2 = (Chapter *) [nsentitydescription insertnewobjectforentityforname:@"Chapter"Inmanagedobjectcontext:context]; Chapter2.name=@"Hello2"; Chapter2.orderid= [NSNumber numberwithint:1]; Chapter2.chapid= [NSNumber numberwithint:101]; Chapter2.mycontent=Content2; //Book ObjectBook *book = (book *) [Nsentitydescription insertnewobjectforentityforname:@" Book"Inmanagedobjectcontext:context]; Book.bookid= [NSNumber numberwithint: -]; Book.name=@"Hello"; Book.author=@"Kitty"; Book.summary=@"Test";    [Book Addmychaptersobject:chapter1];        [Book Addmychaptersobject:chapter2]; //commit to persistent storage    if([context HasChanges]) {[Context Save:nil]; }}//Reading Objects-(void) testread{//get context from AppdelegateAppdelegate *appdelegate = [UIApplication sharedapplication].Delegate; Nsmanagedobjectcontext*context =[Appdelegate Managedobjectcontext]; //Generating a Query object (querying all data)Nsentitydescription *ENTITYDESCR = [nsentitydescription entityforname:@" Book"Inmanagedobjectcontext:context]; Nsfetchrequest*request =[[Nsfetchrequest alloc]init];        [Request SETENTITY:ENTITYDESCR]; //Execute QueryNserror *error; Nsarray*arraybooks = [Context executefetchrequest:request error:&ERROR]; //define how to sort (sort by the OrderID property of the Chapter object in the collection, ascending)Nssortdescriptor *chaptersdescriptor = [Nssortdescriptor sortdescriptorwithkey:@"orderId"Ascending:yes]; //traversing result sets     for(Book *bookincharraybooks) {                //use current object PropertiesNSLog (@"Book name =%@", Book.name); //use the collection properties of the current object to turn to an arrayNsarray *arraychapters =[Book.mychapters allobjects]; //SortArraychapters =[Arraychapters Sortedarrayusingdescriptors:[nsarray Arraywithobjects:chaptersdescriptor,nil]                ]; //iterating through a sub-array         for(Chapter *chapterincharraychapters) {NSLog (@"Chapter name =%@", Chapter.name); Textcontent*content = (textcontent*) chapter.mycontent; NSLog (@"Chapter Text =%@", Content.text); }    }}//Update Object Properties-(void) testupdate{//get context from AppdelegateAppdelegate *appdelegate = [UIApplication sharedapplication].Delegate; Nsmanagedobjectcontext*context =[Appdelegate Managedobjectcontext]; //Generate Request ObjectNsentitydescription *ENTITYDESCR = [nsentitydescription entityforname:@" Book"Inmanagedobjectcontext:context]; Nsfetchrequest*request =[[Nsfetchrequest alloc]init];        [Request SETENTITY:ENTITYDESCR]; //Execute QueryNserror *error; Nsarray*array = [Context executefetchrequest:request error:&ERROR]; //Change Object PropertiesBook * book = array[0]; Book.name=@"BOOKS"; //commit to persistent storage    if([context HasChanges]) {[Context Save:nil]; }}//Delete Object-(void) testremove{//get context from AppdelegateAppdelegate *appdelegate = [UIApplication sharedapplication].Delegate; Nsmanagedobjectcontext*context =[Appdelegate Managedobjectcontext]; //Generate Request ObjectNsentitydescription *ENTITYDESCR = [nsentitydescription entityforname:@" Book"Inmanagedobjectcontext:context]; Nsfetchrequest*request =[[Nsfetchrequest alloc]init];        [Request SETENTITY:ENTITYDESCR]; //Execute QueryNserror *error; Nsarray*array = [Context executefetchrequest:request error:&ERROR]; //traverse the Delete object, because the gatekeeper is set to cascade in the model, so the sub-object is automatically deleted     for(Book *bookinchArray)    {[Context Deleteobject:book]; }        //commit to persistent storage    if([context HasChanges]) {[Context Save:nil]; }}

Ios:core Data Entry