ios - 如何使用 NSMutableArray 的内容填充 Core Data/SQLite DB

Question

我有一个名为 usersArray 的 NSMutableArray，我想将其填充到核心数据/SQLite 数据库/存储中。到目前为止，我已经构建了以下方法，但我认为它不会正确填充，我们将不胜感激任何帮助。

- (void)populateCDDB:(NSMutableArray *)usersArray {

    NSData *arrayData = [NSKeyedArchiver archivedDataWithRootObject:usersArray];

    NSFetchRequest *request = [[NSFetchRequest alloc] init];
    [request setEntity:[NSEntityDescription entityForName:@"Account" inManagedObjectContext:_context]];

    NSError *error = nil;
    NSArray *objectsForImport = [_context executeFetchRequest:request error:&error];
    NSArray *importKeys = [NSArray arrayWithObjects:@"username", @"pin", @"credit", @"email", @"lastLogin", @"rfid", @"phoneNumber", nil];

    for (NSManagedObject *object in objectsForImport) {
//        NSMutableArray *anObjectArray = [NSMutableArray arrayWithCapacity:[importKeys count]];
        for (NSString *key in importKeys) {
            id value = [object valueForKey:key];
            if (!value) {
                value = @"";
            }
            [usersArray addObject:[value description]];
        }
    }
    //save the results to Core Data / SQLite store.
    [_context save:&error];
}

是的，usersArray 是该类的一个实例变量。

Answer 1

好的，我理解评论的意思是您想要使用数组中的对象作为在核心数据中创建“帐户”对象的来源。

根据问题收集的数据，我假设数组中的对象和核心数据“帐户”实体都支持所有键。

由于您没有为数组中的对象指定类型或 API，我假设它们与您之前列出的名称的键值兼容，并且类型兼容。

- (BOOL)addUsersFromArray:(NSArray*)usersToAdd
                  intoMOC:(NSManagedObjectContext*)moc
                    error:(NSError**)error {
    NSArray *importKeys = @[@"pin", @"credit", @"email", @"lastLogin", @"rfid", @"phoneNumber"];
    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Account"];
    for (id user in usersToAdd) {
        id username = [user valueForKey:@"username"];
        // See if we already have an Account for this user - username is unique key
        fetchRequest.predicate = [NSPredicate predicateWithFormat:@"username = %@", username];
        NSArray *fetched = [moc executeFetchRequest:fetchRequest error:error];
        if (fetched == nil) return NO;

        NSManagedObject *account = [fetched firstObject];
        if (account == nil) {
            account = [NSEntityDescription insertNewObjectForEntityForName:@"Account" inManagedObjectContext:moc];
            [account setValue:username forKey:@"username"];
        }
        for (NSString *key in importKeys) {
            id value = [user valueForKey:key];
            if (value) {
                [account setValue:value forKey:key];
            }
        }

    }
    return YES;
}