ios - How to copy sqlite database when we clicked on a UIButton? -

i storing details coredata nsstring.

 nsentitydescription *entitydesc=[nsentitydescription entityforname:@"addnewvehicle" inmanagedobjectcontext:self.managedobjectcontext];  nsmanagedobject *newobject=[[nsmanagedobject alloc]initwithentity:entitydesc insertintomanagedobjectcontext:self.managedobjectcontext]; nserror *error;          nsstring *instr = [nsstring stringwithformat: @"%d", (int)x];         [newobject setvalue:instr forkey:@"slno"];         [newobject setvalue:txt_platename.text forkey:@"platenumber"];         [newobject setvalue:txt_vehiclename.text forkey:@"vname"];         [self.managedobjectcontext save:&error]; 

also have 2 buttons named backup button , restore button.when cilck on backup button, current core data must duplicate coredatabackup.sqlite. tried following way:-

 - (ibaction)savedata:(id)sender {      nsstring * databasename = @"coredata.sqlite";     nsstring * databasebackupname = @"coredatabackup.sqlite";     nsfilemanager *filemanager = [nsfilemanager defaultmanager];     nserror *error = nil;     nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes);     nsstring *documentsdir = ([paths count] > 0) ? [paths objectatindex:0] : nil;      nsstring *backuppath = [documentsdir stringbyappendingpathcomponent:databasebackupname];     nsstring *dbpath = [documentsdir stringbyappendingpathcomponent:databasename];      nsurl *tourl = [nsurl fileurlwithpath:backuppath];      if([filemanager fileexistsatpath:backuppath])     {         nslog(@"checks backuppath present ?? success");         //get rid of old copy, 1 allowed         [filemanager removeitematpath:backuppath error:&error];     }      if([filemanager fileexistsatpath:dbpath])     {         if ([filemanager copyitematpath:dbpath topath:backuppath error:&error]) {             nslog(@"creates backup");             [tourl setresourcevalue:[nsnumber numberwithbool:yes] forkey:nsurlisexcludedfrombackupkey error:&error];         } else {             nslog(@"failed create writable database file message '%@'.", [error localizeddescription]);         }     }} 

result creates coredatabackup.sqlite file on documents folder.but not copying current coredata details new file. don't know how create coredata.please 1 give useful advice.thanks in advance

you should disable wal mode in persistentstorecoordinator method of appdelegate

 nserror *error = nil; _persistentstorecoordinator = [[nspersistentstorecoordinator alloc] initwithmanagedobjectmodel:[self managedobjectmodel]]; nsmutabledictionary *pragmaoptions = [nsmutabledictionary dictionary];  /*attetion: disable wal mode*/ [pragmaoptions setobject:@"delete" forkey:@"journal_mode"]; nsnumber *optionyes = [nsnumber numberwithbool:yes]; nsdictionary *options = [nsdictionary dictionarywithobjectsandkeys:                          [nsnumber numberwithbool:yes], nsmigratepersistentstoresautomaticallyoption,                          [nsnumber numberwithbool:yes], nsinfermappingmodelautomaticallyoption,                          pragmaoptions, nssqlitepragmasoption,                          optionyes,nsmigratepersistentstoresautomaticallyoption ,nil]; if (![_persistentstorecoordinator addpersistentstorewithtype:nssqlitestoretype configuration:nil url:storeurl options:options error:&error]) {     abort(); }