Delete/Reset all entries in Core Data?

Question

Do you know of any way to delete all of the entries stored in Core Data? My schema should stay the same; I just want to reset it to blank.

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Edit

Answer 1

MagicalRecord makes this very easy.

[MyCoreDataObject MR_truncateAll];

Answer 2

iOS 10 + Swift 3 solution:

func clearCoreDataStore() {
    let delegate = UIApplication.shared.delegate as! AppDelegate
    let context = delegate.persistentContainer.viewContext

    for i in 0...delegate.persistentContainer.managedObjectModel.entities.count-1 {
        let entity = delegate.persistentContainer.managedObjectModel.entities[i]

        do {
            let query = NSFetchRequest<NSFetchRequestResult>(entityName: entity.name!)
            let deleterequest = NSBatchDeleteRequest(fetchRequest: query)
            try context.execute(deleterequest)
            try context.save()

        } catch let error as NSError {
            print("Error: \(error.localizedDescription)")
            abort()
        }
    }
}

Iterates through all of the core data entities and clears them

Answer 3

Several good answers to this question. Here's a nice concise one. The first two lines delete the sqlite database. Then the for: loop deletes any objects in the managedObjectContext memory.

NSURL *storeURL = [[(FXYAppDelegate*)[[UIApplication sharedApplication] delegate] applicationDocumentsDirectory] URLByAppendingPathComponent:@"AppName.sqlite"];
[[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil];
for (NSManagedObject *ct in [self.managedObjectContext registeredObjects]) {
    [self.managedObjectContext deleteObject:ct];
}

Answer 4

Thanks for the post. I followed it and it worked for me. But I had another issue that was not mentioned in any of the replies. So I am not sure if it was just me.

Anyway, thought I would post here the problem and my way that solved it.

I had a few records in the database, I wanted to purge everything clean before write new data to the db, so I did everything including

[[NSFileManager defaultManager] removeItemAtURL:storeURL error:&error]; 

and then used managedObjectContext to access the database (supposed to be empty by now), somehow the data was still there. After a while of troubleshooting, I found that I need to reset managedObjectContext, managedObject, managedObjectModel and persistentStoreCoordinator, before I use managedObjectContext to access the dabase. Now I have a clean database to write to.

Answer 5

Delete sqlite from your fileURLPath and then build.

Answer 6

As a quick reference to save searching elsewhere - recreating the persistent store after deleting it can be done with:

if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
// do something with the error
}