Remove sqlite database and replace with default from bundle - ios

Question

I used the Master-Detail-Application example at Xcode 4.3.3 to develope a data viewer. The app is downloading several files and append each file to a cell at the tableview. everything works fine. but if the user starts the download again, I need to remove all the previous data from the database and the tableview.
I ended up with the following steps:
remove the old store from coordinator
remove the old sqlite database file
copy the default ( empty ) sqlite db file from the bundle dir into the doc dir
update store coordinator
update tableview.
but now the problem is, that if I do so, the new data is not written into sqlite file.
Please, can someone check my code. The following code is located at the MasterViewController.m ! I working on this since several days and I am totally stuck !!!
Thank you!
NSLog(#"Delete existing database file and copy default from bundle dir!");
NSFileManager* fileManager = [[NSFileManager alloc] init];
fileManager = [[NSFileManager alloc] init];
NSError *error = nil;
//get the documents directory:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
// create database path documents dir
NSString *databasepath = [documentsDirectory stringByAppendingPathComponent:#"MyDatabase.sqlite"];
NSLog(#"Destination Database Path = %#", databasepath);
// create database path bundle dir
NSString *resourceDBFolderPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"MyDatabase.sqlite"];
NSLog(#"Recource Database Path = %#", resourceDBFolderPath);
// remove old store from coordinator
error = nil;
NSManagedObjectModel *managedObjectModel;
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"MyDatabase" withExtension:#"momd"];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
NSPersistentStoreCoordinator *persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]];
NSURL *applicationDocumentsDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *storeURL = [applicationDocumentsDirectory URLByAppendingPathComponent:#"MyDatabase.sqlite"];
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
if (error != nil){
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
}
NSPersistentStore *persistentStore = [[persistentStoreCoordinator persistentStores] objectAtIndex:0];
[persistentStoreCoordinator removePersistentStore:persistentStore error:&error];
if (error)
if (error != nil){
NSLog(#"error removing persistent store %# %#", error, [error userInfo]);
}
// Remove old database file
[[NSFileManager defaultManager] removeItemAtPath: [documentsDirectory stringByAppendingPathComponent: #"MyDatabase.sqlite"] error: &error];
if (error != nil){
NSLog(#"delete Database status: %#", [error localizedDescription]);
}
// copy default empty database file into documents dir
[fileManager copyItemAtPath: resourceDBFolderPath toPath: databasepath
error: &error];
if (error != nil){
NSLog(#"copy default Database status: %#", [error localizedDescription]);
}
// then update storecoordinator
// add clean store file back by adding a new persistent store with the same store URL
if (![persistentStoreCoordinator addPersistentStoreWithType: NSSQLiteStoreType
configuration: nil
URL: storeURL
options: nil
error: &error]) {
NSLog(#"failed to add db file, error %#, %#", error, [error userInfo]);
}
NSLog(#"Database replacement end!");