您还可以查找所有实体名称，并按名称删除它们。它是一个较长的版本，但工作得很好，这样你就不必使用持久性存储

 - (void)clearCoreData
{
NSError *error;
NSEntityDescription *des = [NSEntityDescription entityForName:@"Any_Entity_Name" inManagedObjectContext:_managedObjectContext];
NSManagedObjectModel *model = [des managedObjectModel];
NSArray *entityNames = [[model entities] valueForKey:@"name"];

for (NSString *entityName in entityNames){

    NSFetchRequest *deleteAll = [NSFetchRequest fetchRequestWithEntityName:entityName];
    NSArray *matches = [self.database.managedObjectContext executeFetchRequest:deleteAll error:&error];

}
    if (matches.count > 0){
        for (id obj in matches){

            [_managedObjectContext deleteObject:obj];
        }
       [self.database.managedObjectContext save:&error];
    }
}

对于“Any_Entity_Name”，只需要给出任何一个实体的名称，我们只需要找出实体的实体描述。ValueForKey@"name"将返回所有实体名称。最后，别忘了保存。

删除持久存储文件并设置一个新的持久存储协调器?

这里我的swift3版本删除所有记录。'Users'是实体名称

@IBAction func btnDelAll_touchupinside(_ sender: Any) {

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let managedObjectContext = appDelegate.persistentContainer.viewContext

    let fetchReq = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
    let req = NSBatchDeleteRequest(fetchRequest: fetchReq)

    do {
        try managedObjectContext.execute(req)

    } catch {
        // Error Handling
    }   
}

iOS 10和Swift 3

假设您的实体名称是“Photo”，并且您创建了一个CoreDataStack类…

 func clearData() {
        do {            
            let context = CoreDataStack.sharedInstance.persistentContainer.viewContext
            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Photo")
            do {
                let objects  = try context.fetch(fetchRequest) as? [NSManagedObject]
                _ = objects.map{$0.map{context.delete($0)}}
                CoreDataStack.sharedInstance.saveContext()
            } catch let error {
                print("ERROR DELETING : \(error)")
            }
        }
    }

这里有一个很好的教程，教你如何使用CoreData以及如何使用这个方法。 https://medium.com/compileswift/parsing-json-response-and-save-it-in-coredata-step-by-step-fb58fc6ce16f#.1tu6kt8qb

如果你想删除所有对象(这比拆除Core Data堆栈简单得多，但性能较差)，那么这是一个更好的实现:

- (void)deleteAllManagedObjectsInModel:(NSManagedObjectModel *)managedObjectModel context:(NSManagedObjectContext *)managedObjectContext
{
    NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
        [managedObjectContext performBlockAndWait:^{
            for (NSEntityDescription *entity in managedObjectModel) {
                NSFetchRequest *fetchRequest = [NSFetchRequest new];
                [fetchRequest setEntity:entity];
                [fetchRequest setIncludesSubentities:NO];
                NSArray *objects = [managedObjectContext executeFetchRequest:fetchRequest error:nil];
                for (NSManagedObject *managedObject in objects) {
                    [managedObjectContext deleteObject:managedObject];
                }            
            }

            [managedObjectContext save:nil];
        }];
    }];
    [operation setCompletionBlock:^{
        // Do stuff once the truncation is complete
    }];
    [operation start];
}

这个实现利用NSOperation来执行主线程的删除，并在完成时通知。您可能希望在完成块中发出通知或其他内容，以便将状态冒泡回主线程。

[对请求更新回复的赏金的响应延迟]

回顾之前的答案，

Fetching and deleting all items, as suggested by @Grouchal and others, is still an effective and useful solution. If you have very large data stores then it might be slow, but it still works very well. Simply removing the data store is, as you and @groundhog note, no longer effective. It's obsolete even if you don't use external binary storage because iOS 7 uses WAL mode for SQLite journalling. With WAL mode there may be (potentially large) journal files sitting around for any Core Data persistent store.

But there's a different, similar approach to removing the persistent store that does work. The key is to put your persistent store file in its own sub-directory that doesn't contain anything else. Don't just stick it in the documents directory (or wherever), create a new sub-directory just for the persistent store. The contents of that directory will end up being the persistent store file, the journal files, and the external binary files. If you want to nuke the entire data store, delete that directory and they'll all disappear.

在设置持久化存储时，你会这样做:

NSURL *storeDirectoryURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"persistent-store"];
if ([[NSFileManager defaultManager] createDirectoryAtURL:storeDirectoryURL
        withIntermediateDirectories:NO
        attributes:nil
        error:nil]) {
    NSURL *storeURL = [storeDirectoryURL URLByAppendingPathComponent:@"MyApp.sqlite"];
    // continue with storeURL as usual...
}

然后当你想把商店搬走的时候，

[[NSFileManager defaultManager] removeItemAtURL:storeDirectoryURL error:nil];

这将递归地删除自定义子目录和其中的所有Core Data文件。

这只在您没有将持久存储与其他重要数据放在同一个文件夹中时才有效。比如documents目录，其中可能有其他有用的东西。如果这是您的情况，您可以通过查找您想要保留的文件并删除所有其他文件来获得相同的效果。喜欢的东西:

NSString *docsDirectoryPath = [[self applicationDocumentsDirectory] path];
NSArray *docsDirectoryContents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:docsDirectoryPath error:nil];
for (NSString *docsDirectoryItem in docsDirectoryContents) {
    // Look at docsDirectoryItem. If it's something you want to keep, do nothing.
    // If it's something you don't recognize, remove it.
}

这种方法可能容易出错。你必须绝对确定你知道你想要保存的每一个文件，否则你可能会删除重要的数据。另一方面，您可以删除外部二进制文件，而不需要知道用于存储它们的文件/目录名称。