Data Persistence with CoreData - core-data

Question

Hi everybody I have a problem using CoreData Persistence, my problem is, when I launch my application I manage to add some data (from a form within the app) to my DataBase and display them with using NSLog.
But actually I think all these data disappear when I stop the ipad emulator and re launch it after..
So i don't really know if it comes from my code or if it's because of the emulator.
I made a diagram to show you the architecture of my app and my entities:
The problem is that i'm using different viewController so i need to pass the ManagedObjectModel to each one. My form is in the newDocumentViewController, when i add somme entities i would like to access them in all the others viewController and save it to the app local storage.
Here is some code to show you a bit:
AppDelegate.m
#synthesize managedObjectContext = __managedObjectContext;
#synthesize managedObjectModel = __managedObjectModel;
#synthesize persistentStoreCoordinator = __persistentStoreCoordinator;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
DetailViewController *detailViewController = [[DetailViewController alloc] initWithNibName:#"DetailViewController" bundle:nil];
UINavigationController *detailNavigationController = [[UINavigationController alloc] initWithRootViewController:detailViewController];
MasterViewController *masterViewController = [[MasterViewController alloc] initWithNibName:#"MasterViewController" bundle:nil];
UINavigationController *masterNavigationController = [[UINavigationController alloc] initWithRootViewController:masterViewController];
masterViewController.managedObjectContext = self.managedObjectContext;
detailViewController.managedObjectContext = self.managedObjectContext;
I have those properties within each masterViewController and DetailViewController (and from DetailViewController to NewDocumenViewController) to receive the objectContext
#property (nonatomic,strong) NSManagedObjectContext *managedObjectContext;
So with this i don't really know how to access my data from each controller and is the data is stored locally by doing like this:
NewDocumentController.m
-(void) addNewDocument:(NSString*)name with_niveau:(NSInteger)level{
Document *doc = [NSEntityDescription insertNewObjectForEntityForName:#"Document" inManagedObjectContext:managedObjectContext];
doc.nom=name;
doc.niveau=[NSNumber numberWithInteger:level];
}
-(void) addNewDocument_info:(NSString*)name with_createur:(NSString*)createur with_dateModif:(NSDate*)date1 with_status:(BOOL)etat{
DocumentInfo *doc_info = [NSEntityDescription insertNewObjectForEntityForName:#"DocumentInfo" inManagedObjectContext:managedObjectContext];
doc_info.nom =name;
doc_info.createur=createur;
doc_info.date_creation=[NSDate date];
doc_info.date_modification=date1;
doc_info.status= [NSNumber numberWithBool:etat];
}

Answer 1

You need to save your data:
NSError *error = nil;
[self.managedObjectContext save:&error];