ios - Update Core Data with JSON Key Value ( id ) -

i having problem updating core data. downloading data in background thread comparing identifier in core data , count having trouble update want check identifier present in core data json response , if id present in json response leave , if not present in json response (that means record has been removed in server side)

here in code checking id present in core data or not , want check id present in json or not update records

any great appreciate in advance please check code how storing data in core data

for (int = 0; < [arraydata count]; i++) {         nsnumber * idnum = [arraydata objectatindex:i][@"id"];         nsfetchrequest *request = [nsfetchrequest fetchrequestwithentityname:@"deal"];         [request setpredicate:[nspredicate predicatewithformat:@"identifier == %@",idnum]];         [request setfetchlimit:1];         nsuinteger count = [_managedobjectcontext countforfetchrequest:request error:&error];         if (count == nsnotfound) {             nslog(@"error");         }else if (count == 0) {             deal * dealsentity = [nsentitydescription insertnewobjectforentityforname:@"deal" inmanagedobjectcontext:_managedobjectcontext];             nsstring * name  = [arraydata objectatindex:i][@"name"];             dealsentity.nameattribute = name;             dealsentity.identifier = idnum;             [appdelegate savecontext];         }         [self performselectoronmainthread:@selector(updatedata:) withobject:_myarray waituntildone:yes];     }  - (void) updatedata:(nsarray *)yourdata {     nsfetchrequest *fetchrequest = [[nsfetchrequest alloc]init];     nsentitydescription *entity = [nsentitydescription entityforname:@"deal" inmanagedobjectcontext:_managedobjectcontext];     [fetchrequest setreturnsobjectsasfaults:no];     [fetchrequest setentity:entity];     nserror *error;     yourdata = [_managedobjectcontext executefetchrequest:fetchrequest error:&error];     self.myarray = yourdata;     [listtableview reloaddata]; } 

i have tried updating or deleting records coredata

for (int d = 0; d < [_myarray count]; d++) {         deal * deal = (deal*)_myarray[d];         nsnumber * identifier = [deal identifier];         if ([identifier isequaltonumber:[[arraydata objectatindex:d] valueforkey:@"id"]] ) {             nslog(@"equal %d",d);         } else {             nslog(@"kill ");         }     } 

but here problem coredata has 115 records when checking json json have 114 records , returns crash

as have identifier database need change code little bit

nsfetchrequest *request = [[nsfetchrequest alloc] init]; [request setentity:[nsentitydescription entityforname:@"deal" inmanagedobjectcontext:moc]]; [request setpredicate:[nspredicate predicatewithformat:@"identifier == %@",idnum]]; [request setfetchlimit:1];  nserror *error = nil; nsarray *results = [moc executefetchrequest:request error:&error];  // check count   if([results count] == 1) {    // update coredata object } else {    // create new object  }