尝试从 class 内部而不是外部获取游标时获取 MySQL 连接不可用

Question

我在 OS X 10.9 上运行 mariadb 数据库并尝试通过 python.

连接到它

如果我尝试此代码，它运行良好

import mysql.connector as mariadb

if __name__ == "__main__":

    mariadb_connection = mariadb.connect(user='root', database='account_balances')
    cursor = mariadb_connection.cursor()

我可以事件插入一些记录

但如果我尝试以下

class account(object):
    _logging_to_db_enabled = False
    _database_object = None
    _database_cursor = None

def __init__(self):
    pass

def enable_logging_to_db(self):
    try:
        self._database_object = mariadb.connect(mariadb.connect(user='root', database='account_balances'))
        self._logging_to_db_enabled = True
    except self._database_object.Error as error:
        print ("Opening DB error: {}".format(error))

    self._database_cursor = self._database_object.cursor()

if __name__ == "__main__":

    testobject = account()
    testobject.enable_logging_to_db()

我收到这个错误

File "....", line 22, in enable_logging_to_db
self._database_cursor = self._database_object.cursor()
File "<pathname_deleted>", line 1372, in cursor
raise errors.OperationalError("MySQL Connection not available.")
mysql.connector.errors.OperationalError: MySQL Connection not available.

有人知道为什么这在 main 中有效但在对象中无效吗？

Answer 1

因为你有typo/copy&粘贴错误:

self._database_object = mariadb.connect(mariadb.connect(user='root', database='account_balances'))

应该是：

self._database_object = mariadb.connect(user='root', database='account_balances')

尝试从 class 内部而不是外部获取游标时获取 MySQL 连接不可用

Getting MySQL Connection not available when trying to get a cursor from inside a class but not from outside

python

mysql

mariadb