如果需要删除所有对象且不删除备份文件，可以使用以下方法:

- (void)deleteAllObjectsInContext:(NSManagedObjectContext *)context
                       usingModel:(NSManagedObjectModel *)model
{
    NSArray *entities = model.entities;
    for (NSEntityDescription *entityDescription in entities) {
        [self deleteAllObjectsWithEntityName:entityDescription.name
                                   inContext:context];
    }
}

- (void)deleteAllObjectsWithEntityName:(NSString *)entityName
                             inContext:(NSManagedObjectContext *)context
{
    NSFetchRequest *fetchRequest =
        [NSFetchRequest fetchRequestWithEntityName:entityName];
    fetchRequest.includesPropertyValues = NO;
    fetchRequest.includesSubentities = NO;

    NSError *error;
    NSArray *items = [context executeFetchRequest:fetchRequest error:&error];

    for (NSManagedObject *managedObject in items) {
        [context deleteObject:managedObject];
        NSLog(@"Deleted %@", entityName);
    }
}

注意它可能非常慢(取决于对象图中有多少对象)。

如果需要删除所有对象且不删除备份文件，可以使用以下方法:

- (void)deleteAllObjectsInContext:(NSManagedObjectContext *)context
                       usingModel:(NSManagedObjectModel *)model
{
    NSArray *entities = model.entities;
    for (NSEntityDescription *entityDescription in entities) {
        [self deleteAllObjectsWithEntityName:entityDescription.name
                                   inContext:context];
    }
}

- (void)deleteAllObjectsWithEntityName:(NSString *)entityName
                             inContext:(NSManagedObjectContext *)context
{
    NSFetchRequest *fetchRequest =
        [NSFetchRequest fetchRequestWithEntityName:entityName];
    fetchRequest.includesPropertyValues = NO;
    fetchRequest.includesSubentities = NO;

    NSError *error;
    NSArray *items = [context executeFetchRequest:fetchRequest error:&error];

    for (NSManagedObject *managedObject in items) {
        [context deleteObject:managedObject];
        NSLog(@"Deleted %@", entityName);
    }
}

注意它可能非常慢(取决于对象图中有多少对象)。

下面这个版本可以删除每个表中的每条记录。

斯威夫特4

static func resetDatabase() {
    do {
        try dataStore.persistentStoreCoordinator.managedObjectModel.entities.forEach { (entity) in
            if let name = entity.name {
                let fetch = NSFetchRequest<NSFetchRequestResult>(entityName: name)
                let request = NSBatchDeleteRequest(fetchRequest: fetch)
                try mainContext.execute(request)
            }
        }

        try mainContext.save()
    } catch {
        print("error resenting the database: \(error.localizedDescription)")
    }
}

使用这个

+(NSArray *)fetchDataFromEntity:(NSString *)entityName context:(NSManagedObjectContext *)context
{
    NSFetchRequest * fetchRequest =[[NSFetchRequest alloc] init];
    NSEntityDescription * CategoriesEntity = [NSEntityDescription entityForName:entityName inManagedObjectContext:context];
    [fetchRequest setEntity:CategoriesEntity];

    NSError * error;
    NSInteger count = [context countForFetchRequest:fetchRequest error:&error];

    if (count && count>0) {

        NSArray * fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
        if (fetchedObjects && fetchedObjects.count>0) {

            return fetchedObjects;
        }else
            return nil;

    }
    else
        return nil;
}
+ (void)deleteObjectsOfArray:(NSMutableArray*)ary context:(NSManagedObjectContext *)context {
    for (NSManagedObject * obj in ary) {
        [context deleteObject:obj];
    }
    NSError *saveError = nil;
    [context save:&saveError];
}
+ (void)deleteEntity:(NSString *)entityName context:(NSManagedObjectContext *)context {
    NSArray *listArray = [self fetchDataFromEntity:entityName context:context];
    [self deleteObjectsOfArray:[NSMutableArray arrayWithArray:listArray] context:context];
}

龙道9+ Swift 2

删除所有实体中的所有对象

func clearCoreDataStore() {
    let entities = managedObjectModel.entities
    for entity in entities {
        let fetchRequest = NSFetchRequest(entityName: entity.name!)
        let deleteReqest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
        do {
            try context.executeRequest(deleteReqest)
        } catch {
            print(error)
        }
    }
}

Swift 5.1解决方案

public static func reset() {
    let coordinator = _persistentContainer.persistentStoreCoordinator
    for store in coordinator.persistentStores where store.url != nil {
        try? coordinator.remove(store)
        try? FileManager.default.removeItem(atPath: store.url!.path)
    }
}