python mysqldb游标消息列表显示两次错误

Question

由于某些原因，每当我在db游标上运行查询时，它在其.messages列表中生成两个错误，这是一个特性吗？

下面是运行查询的代码，应用程序所做的就是打开到数据库的连接，运行一次强制错误，读取.messages，然后退出

import MySQLdb

class dbobject:
    def __init__(self, dbhost, dbuser, dbpass, dbname):
        self.connection = MySQLdb.connect( user=dbuser, passwd=dbpass, host=dbhost, db=dbname )
        self.cursor = self.connection.cursor()

    def try_query(self, query, args=()):
        """ attempts to run a query, where
                query is the query to be run, with '%s' statements where the values should be, and
                args is a tuple of the values to go with the query"""
        try:
            if args == ():
                self.cursor.execute(query)
            else:
                self.cursor.execute(query, args)
            self.connection.commit()
        except:

            self.connection.rollback()

    def add_unit(self, name, version, credits):
        """ takes name, version, credits
                name is the name of the unit paper
                version is the unit version, and
                credits is how many credits its worth"""
        self.try_query("insert into dsfdf tbl_unit (unit_name, unit_version, unit_credits) values (%s,%s,%s)",(name,version,credits))

    def close(self):
        self.cursor.close()
        self.connection.close()


blah = dbobject(#####################)
blah.add_unit( "thing", "something", 6)
for i in blah.cursor.messages:
    print i
blah.close()

Answer 1

也许您可以发布您收到的消息。

mysql_insert_etc.py:22:警告:第1行的列'val‘的数据被截断

self.cursor.execute(query，args) (，('Warning'，1265L，“第1行'val‘列的数据被截断”)

从上面(制造的错误)可以看出，MySQLdb返回：

1. MySQL warning，
2. 自己的异常。

使用下面的代码，您可以禁止显示警告，也可以让警告引发异常。

引发异常(对this example稍作修改)：

from warnings import catch_warnings, simplefilter

def try_query(self, query, args=()):
    with catch_warnings():
        simplefilter('error', MySQLdb.Warning)
        try:
            if args == ():
                self.cursor.execute(query)
            else:
                self.cursor.execute(query, args)
            self.connection.commit()
        except MySQLdb.Error, e:
            self.connection.rollback()
            raise e

Suppress warnings (from here)：

from warnings import filterwarnings

filterwarnings('ignore', category=MySQLdb.Warning)