instance has no attribute (python)

Question

I have a weird issue, which is probably easy to resolve.

I have a class Database with an __init__ and an executeDictMore method (among others).

class Database():
    def __init__(self, database, server,login, password ):
        self.database = database
        my_conv = { FIELD_TYPE.LONG: int }
        self.conn = MySQLdb.Connection(user=login, passwd=password, db=self.database, host=server, conv=my_conv)
        self.cursor = self.conn.cursor()

    def executeDictMore(self, query):
        self.cursor.execute(query)
        data = self.cursor.fetchall()
        if data == None :
            return None
        result = []
        for d in data:
            desc = self.cursor.description
            dict = {}
            for (name, value) in zip(desc, d) :
                dict[name[0]] = value
            result.append(dict)
        return result

Then I instantiate this class in a file db_functions.py :

from Database import Database
db = Database()

And I call the executeDictMore method from a function of db_functions :

def test(id):
    query = "SELECT * FROM table WHERE table_id=%s;" %(id)
    return db.executeDictMore(query)

Now comes the weird part. If I import db_functions and call db_functions.test(id) from a python console:

import db_functions
t = db_functions.test(12)

it works just fine. But if I do the same thing from another python file I get the following error :

AttributeError: Database instance has no attribute 'executeDictMore'

I really don't understand what is going on here. I don't think I have another Database class interfering. And I append the folder where the modules are in sys.path, so it should call the right module anyway.

If someone has an idea, it's very welcome.

Answer 1

You have another Database module or package in your path somewhere, and it is getting imported instead.

To diagnose where that other module is living, add:

import Database
print Database.__file__

before the from Database import Database line; it'll print the filename of the module. You'll have to rename one or the other module to not conflict.

Answer 2

如果要首先在搜索路径中插入（而不是追加）到sys.path中：

sys.path.insert(0, '/path/to/your/Database/class')

Answer 3

You could at least try to avoid SQL injection. Python provides such neat ways to do so:

def executeDictMore(self, query, data=None):
    self.cursor.execute(query, data)

and

def test(id):
    query = "SELECT * FROM table WHERE table_id=%s"
    return db.executeDictMore(query, id)

are the ways to do so.

Sorry, this should rather be a comment, but an answer allows for better formatting. Iam aware that it doesn't answer your question...

Answer 4

我不太确定出什么问题了，但是您可以尝试将数据库对象作为参数传递给函数，例如db_functions.test(db, 12) ，而db是您的Database类