LightMysql：为方便操作MySQL而封装的Python类

原文链接：http://www.danfengcao.info/python/2015/12/26/lightweight-python-mysql-class.html

mysqldb是Python操作MySQL数据库的一个常用包。但在使用过程中，我认为用起来还不够简便。为此，我在mysqldb的基础上封装了一个Python类LightMysql。

先来看如何使用

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from LightMysql import LightMysql

if __name__ == '__main__':

# 配置信息，其中host, port, user, passwd, db为必需
dbconfig = {'host':'127.0.0.1',
'port': 3306,
'user':'danfengcao',
'passwd':'123456',
'db':'test',
'charset':'utf8'}

db = LightMysql(dbconfig) # 创建LightMysql对象，若连接超时，会自动重连

# 查找(select, show)都使用query()函数
sql_select = "SELECT * FROM Customer"
result_all = db.query(sql_select) # 返回全部数据
result_count = db.query(sql_select, 'count') # 返回有多少行
result_one = db.query(sql_select, 'one') # 返回一行

# 增删改都使用dml()函数
sql_update = "update Customer set Cost=2 where Id=2"
result_update = db.dml(sql_update)
sql_delete = "delete from Customer where Id=2"
result_delete = db.dml(sql_delete)

db.close() # 操作结束，关闭对象

使用前需安装

LightMysql完整代码

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import MySQLdb
import time, re

class LightMysql:
"""Lightweight python class connects to MySQL. """

_dbconfig = None
_cursor = None
_connect = None
_error_code = '' # error_code from MySQLdb

TIMEOUT_DEADLINE = 30 # quit connect if beyond 30S
TIMEOUT_THREAD = 10 # threadhold of one connect
TIMEOUT_TOTAL = 0 # total time the connects have waste

def __init__(self, dbconfig):

try:
self._dbconfig = dbconfig
self.dbconfig_test(dbconfig)
self._connect = MySQLdb.connect(
host=self._dbconfig['host'],
port=self._dbconfig['port'],
user=self._dbconfig['user'],
passwd=self._dbconfig['passwd'],
db=self._dbconfig['db'],
charset=self._dbconfig['charset'],
connect_timeout=self.TIMEOUT_THREAD)
except MySQLdb.Error, e:
self._error_code = e.args[0]
error_msg = "%s --- %s" % (time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time())), type(e).__name__), e.args[0], e.args[1]
print error_msg

# reconnect if not reach TIMEOUT_DEADLINE.
if self.TIMEOUT_TOTAL < self.TIMEOUT_DEADLINE:
interval = 0
self.TIMEOUT_TOTAL += (interval + self.TIMEOUT_THREAD)
time.sleep(interval)
return self.__init__(dbconfig)
raise Exception(error_msg)

self._cursor = self._connect.cursor(MySQLdb.cursors.DictCursor)

def dbconfig_test(self, dbconfig):
flag = True
if type(dbconfig) is not dict:
print 'dbconfig is not dict'
flag = False
else:
for key in ['host','port','user','passwd','db']:
if not dbconfig.has_key(key):
print "dbconfig error: do not have %s" % key
flag = False
if not dbconfig.has_key('charset'):
self._dbconfig['charset'] = 'utf8'

if not flag:
raise Exception('Dbconfig Error')
return flag

def query(self, sql, ret_type='all'):
try:
self._cursor.execute("SET NAMES utf8")
self._cursor.execute(sql)
if ret_type == 'all':
return self.rows2array(self._cursor.fetchall())
elif ret_type == 'one':
return self._cursor.fetchone()
elif ret_type == 'count':
return self._cursor.rowcount
except MySQLdb.Error, e:
self._error_code = e.args[0]
print "Mysql execute error:",e.args[0],e.args[1]
return False

def dml(self, sql):
'''update or delete or insert'''
try:
self._cursor.execute("SET NAMES utf8")
self._cursor.execute(sql)
self._connect.commit()
type = self.dml_type(sql)
# if primary key is auto increase, return inserted ID.
if type == 'insert':
return self._connect.insert_id()
else:
return True
except MySQLdb.Error, e:
self._error_code = e.args[0]
print "Mysql execute error:",e.args[0],e.args[1]
return False

def dml_type(self, sql):
re_dml = re.compile('^(?P<dml>\w+)\s+', re.I)
m = re_dml.match(sql)
if m:
if m.group("dml").lower() == 'delete':
return 'delete'
elif m.group("dml").lower() == 'update':
return 'update'
elif m.group("dml").lower() == 'insert':
return 'insert'
print "%s --- Warning: '%s' is not dml." % (time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time())), sql)
return False

def rows2array(self, data):
'''transfer tuple to array.'''
result = []
for da in data:
if type(da) is not dict:
raise Exception('Format Error: data is not a dict.')
result.append(da)
return result

def __del__(self):
'''free source.'''
try:
self._cursor.close()
self._connect.close()
except:
pass

def close(self):
self.__del__()