python AttributeError: 'NoneType' 对象没有属性 'GetDataStore'

AttributeError: 'NoneType' object has no attribute 'GetDataStore'

提问by pedrofernandes

I guys, I developing a utility in python and i have 2 object the main class and an database helper for get sqlserver data.

伙计们，我在 python 中开发了一个实用程序，我有 2 个对象主类和一个用于获取 sqlserver 数据的数据库助手。

database.py

数据库.py

import _mssql

class sqlserver(object):

    global _host, _userid, _pwd, _db

    def __new__ (self, host, userid, pwd, database):
        _host = host
        _userid = userid
        _pwd = pwd
        _db = database

    def GetDataStore(self, sql):
        conn = _mssql.connect(server='(local)\sqlexpress', user='sa', password='xxx', database='Framework.Data2')
        conn.execute_non_query('CREATE TABLE persons(id INT, name VARCHAR(100))')
        conn.execute_non_query("INSERT INTO persons VALUES(1, 'John Doe')")
        conn.execute_non_query("INSERT INTO persons VALUES(2, 'Jane Doe')") 

gaemodel.py

gaemodel.py

import os
import sys
from fwk import system, types, databases

class helper(object):
    pass

def usage(app_name):
    return "Usage: %s <project name>" % (app_name)

def main(argv):
    _io = system.io()

    project_name = argv[1]
    project_home = os.path.join(_io.CurrentDir(), project_name)

    _db = databases.sqlserver('(local)\sqlexpress', 'sa', 'P1lim07181702', 'Framework.Data2')    
    _db.GetDataStore("select name from sysobjects where xtype = 'U' and name not like 'Meta%'")

    str = "from google.appengine.ext import db"
    #for row in cur:
    #    str += "class %s" % row["name"]

    print cur

if __name__ == "__main__":
    if len(sys.argv) > 1:
        main(sys.argv[1:])
    else:
        print usage(sys.argv[0]);

My problem is when i try run code return me this error

我的问题是当我尝试运行代码时返回此错误

Traceback (most recent call last):
  File "C:\Projectos\FrameworkGAE\src\gaemodel.py", line 28, in <module>
    main(sys.argv[1:])
  File "C:\Projectos\FrameworkGAE\src\gaemodel.py", line 18, in main
_    db. GetDataStore("select name from sysobjects where xtype = 'U' and name not like 'Meta%'")
AttributeError: 'NoneType' object has no attribute 'GetDataStore'

What is wrong ??

怎么了 ？？

采纳答案by codeape

First of all:

首先：

• The __new__method should be named __init__.
• Remove the global _host etc. line

• 该__new__方法应命名为__init__。
• 删除全局 _host 等行

Then change the __init__method:

然后改变__init__方法：

self.host = host
self.userid = userid
etc.

And change GetDataStore:

并改变GetDataStore：

conn = _mssql.connect(server=self.host, user=self.userid, etc.)

That should do the trick.

这应该够了吧。

I suggest you read a bit on object-oriented Python.

我建议你阅读一些关于面向对象的 Python。

回答by SilentGhost

Have a look at what __new__is supposed to be doing and what arguments it's supposed to have. I think you wanted to use __init__and not __new__. The reason for your particular error is that _dbis None.

看看应该做什么__new__以及它应该有什么论点。我想你想使用__init__而不是__new__. 您的特定错误的原因_db是None.

回答by Ned Batchelder

I think you want to change databases.py like this:

我认为您想像这样更改 databases.py：

import _mssql

class sqlserver(object):

    def __init__ (self, host, userid, pwd, database):
        self.host = host
        self.userid = userid
        self.pwd = pwd
        self.db = database

    def GetDataStore(self, sql):
        conn = _mssql.connect(server=self.host, user=self.userid, password=self.pwd, database=self.db)
        conn.execute_non_query('CREATE TABLE persons(id INT, name VARCHAR(100))')
        conn.execute_non_query("INSERT INTO persons VALUES(1, 'John Doe')")
        conn.execute_non_query("INSERT INTO persons VALUES(2, 'Jane Doe')")