python – SQLAlchemy反射：如何查询特定列的数据？

testtable = Table('member', Metadata, autoload=True)

def TestConnection():
    data = None
    loopCounter = 0 
    for data in session.query(testtable).filter_by(is_active=1, is_deleted=0): 
        print(loopCounter + 1, data)
        loopCounter += 1
    if data is None:
        raise Exception ("Could not find any data that matches your query")        
    else:
        print("It worked!")

TestConnection()

上面的查询为我提供了members表中所有列中的所有数据.但我想要的是从列中获取特定数据.例如.我想检索用户名和密码列,但我无法正确获取语法.以下是我到目前为止：

def TestConnection():
    loopCounter = 0 
    for password, username in session.query(testtable).filter_by(is_active=1, is_deleted=0):
        print(loopCounter + 1, data)
        loopCounter += 1
    if data is None:
        raise Exception ("Could not find any data that matches your query")        
    else:
        print("It worked!")

失败并出现错误：

Traceback (most recent call last):
File "/home/workspace/upark/src/monitor.py", line 36, in <module>
TestConnection()
File "/home/workspace/upark/src/monitor.py", line 26, in TestConnection
for password, username in session.query(testtable).filter_by(is_active=1, is_deleted=0):
ValueError: too many values to unpack (expected 2)

我正在使用Oracle的Python3.2,SQLAchemy0.8和mysqlconnector.

编辑：一些轻微的进展

刚刚发现我可以在返回所有结果后“过滤”列,如下所示：

def TestConnection():
    data = None
    loopCounter = 0 
    for data in session.query(testtable).filter_by(is_active=1, is_deleted=0): 
        print(loopCounter + 1, data.password, data.username)
        loopCounter += 1
    if data is None:
        raise Exception ("Could not find any data that matches your query")        
    else:
        print("It worked!")

这会给：

1 pass1 userone
2 pass2 usertwo

但正如你所看到的那样,那是在我把所有专栏都拿回来之后.我想要的只是从我需要的列中获取数据.例如. Members表有10列.我只需要从其中两个中获取数据以提高效率.

def TestConnection():
    data = None
    loopCounter = 0 
    for data in session.query(testtable.c.password, testtable.c.username).filter_by(is_active=1, is_deleted=0): 
        pwd, usr = data
        print(loopCounter + 1, pwd, usr)
        loopCounter += 1
    if data is None:
        raise Exception ("Could not find any data that matches your query")        
    else:
        print("It worked!")