Core Data operation additions and deletions

All operations are based on core data framework related APIs, engineering needs to add coredata.framework support

1. Add nsentitydescription insertnewobjectforentityforname:inmanagedobjectcontext:

Create an entity with the Nsentitydescription factory method

Appdelegate *appdelegate = [UIApplication sharedapplication].delegate;//get nsmanagedobjectcontext Nsmanagedobjectcontext *context = [Appdelegate managedobjectcontext]; Nsmanagedobject *managedobject = Nil;managedobject = [Nsentitydescription insertnewobjectforentityforname: Youentityname Inmanagedobjectcontext:context];//youentityname is a nsstring[managedobject setValue:youKeyValue Forkey:youentitykeyname];//kvo mode assignment value-key//e.g. [ManagedObject setvalue:[name descrition] ForKey: @ " Kentitykeyname "], the entity must include Name property, and its name must be" Kentitykeyname "[Appdelegate savecontext];// Don ' t forget to save the changes

2. Deletion of the context DeleteObject:

Nsmanagedobject * DeleteObject = Youwilldeleteobject;//can Get the object from the query result, which is a nsarray getti Ng by the nsfetchrequest/*e.g. Nsfetchrequest *request = [[Nsfetchrequest alloc] Initwithentityname:kentityna Me]; Nserror *error; Nsarray *objects = [Context executefetchrequest:request error:&error];//choose one object or many objects*/ Appdelegate *delegate = [UIApplication sharedapplication].delegate;    Nsmanagedobjectcontext *context = [delegate managedobjectcontext]; [Context Deleteobject:deleteobject]; [Delegate Savecontext];

3. Change

4. Check

4.1 Find all context Executefetchrequest:error:

Nsmutablearray *_array; Appdelegate *appdelegate = [UIApplication sharedapplication].delegate; Nsmanagedobjectcontext *context = [Appdelegate managedobjectcontext]; Nsfetchrequest *request = [[Nsfetchrequest alloc] initwithentityname:kentityname];    Nserror *error; Nsarray *objects = [Context executefetchrequest:request error:&error];    if (objects = = nil) {    NSLog (@ "There is an error!");} else{    _array = [Nsmutablearray arraywitharray:objects];}

Core Data operation additions and deletions