2017-09-26 51 views
0

需要幫助來通過SQLALCHEMY連接到MySQL時發現問題。 下面是我的嘗試:通過SQLALCHEMY連接到Mysql的Python連接

from sqlalchemy import create_engine 
import pandas 

def return_connection_string(database_name, database_user, database_password, database_host, database_port): 
    try: 
     connection_string = 'mysql+mysqlconnector://' + database_user + ':' + database_password + '@' + database_host + ':' + database_port + '/' + database_name 
     print(connection_string) 
     return connection_string 
    except Exception as e: 
     print('Encountered error while generating connection string for MySQL!') 
     print(e) 

def return_connection_object(database_name, database_user, database_password, database_host, database_port): 
    try: 
     connection_string = return_connection_string(database_name, database_user, database_password, database_host, database_port) 
     engine = create_engine(connection_string).connect() 
     return engine 
    except Exception as e: 
     print('Encountered error while connecting to MySQL database!') 
     print(e) 


mysql_conn = return_connection_object('db_name', 'db_user', 'db_pass', 'xyz.abc.com', '4100') 


df = pandas.read_sql_query('select distinct table_name from information_schema.tables', mysql_conn) 
print(df.shape) 


mysql_conn.close() 

以上腳本的工作完全正常,並返回所需的輸出。 的問題是,當我嘗試基於類的方法如下:

from sqlalchemy import create_engine 
import logging 


class Connection_class(object): 

    def __init__(self): 
     pass 

    def return_connection_string(self, database_name, database_user, database_password, database_host, database_port): 
     try: 
      connection_string = 'mysql+mysqlconnector://' + database_user + ':' + database_password + '@' + database_host + ':' + database_port + '/' + database_name 
      print(connection_string) 
      return connection_string 
     except Exception as e: 
      print('Encountered error while generating connection string for MySQL!') 
      print(e) 

    def return_connection_object(self, database_name, database_user, database_password, database_host, database_port): 
     try: 
      connection_string = self.return_connection_string(database_name, database_user, database_password, database_host, database_port) 
      engine = create_engine(connection_string).connect()    
      return engine 
     except Exception as e: 
      print('Encountered error while connecting to MySQL database!') 
      print(e) 

我包上面的類在一個名爲mysql軟件包。該main.py是如下:

from mysql import connector 
import pandas 

mysql_obj = connector() 
mysql_conn = mysql_obj.return_connection_object('db_name', 'db_user', 'db_pass', 'xyz.abc.com', '4100') 


df = pandas.read_sql_query('select distinct table_name from information_schema.tables', mysql_conn) 

mysql_conn.close() 

我得到的錯誤是: 對象類型「Connection_class」有沒有屬性「paramstyle」

在調試,我發現從return_connection_object功能發起的錯誤,不知何故,當它作爲腳本運行時,完全相同的函數返回連接對象時它返回null。

任何線索都會有幫助。提前致謝。

回答

0

用於包裝的名稱看起來非常通用,可能與其他connnector相沖突。可以嘗試重命名你的模塊和導入的對象,以消除這種可能的錯誤來源。