本文详细介绍如何使用Python的pymysql模块连接并操作MySQL数据库，包括增删改查操作的实现及异常处理，同时提供了一个实用的数据库操作封装类，便于在实际项目中复用。
下载安装
1.安装引入模块
2.Connection对象
3.对象的方法
Cursor对象
对象的方法
举例便于理解
# 导入python操作mysql的模块import pymysql# 获取连接对象conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')# 获取执行工具cur = conn.cursor()# sql语句,增删改#sql = 'select birthday from t_user'sql = 'select id,name,pwd,birthday from t_user'# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数count = cur.execute(sql)print('查询的结果有%s条数据'%count)# 获取第一行dateOne = cur.fetchone()print(dateOne)# 向上移动一行cur.scroll(-1)# 向下移动一行cur.scroll(1)cur.scroll(1,mode='absolute') 绝对的，这里指的是第一行cur.scroll(1,mode='relative') 相对的#获取所有行的数据dataAll = cur.fetchall()print(dataAll)for temp in dataAll: print(temp) print(dataAll[-1][2]) #dataAll[-1]得到的是一个用户所有的信息，dataAll[-1][2]获取最后一个人的密码for temp in cur: print(temp)s = 'id:%s,name:%s,pwd:%s,birthday:%s'for temp in dataAll: print(s%(temp[0],temp[1],temp[2],temp[3]))# 关闭cur.close()conn.close()
import pymysql
# 获取连接对象
conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')
# 获取执行工具
cur = conn.cursor()
# sql语句,增删改
#sql = 'select birthday from t_user'
sql = 'select id,name,pwd,birthday from t_user'
# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数
count = cur.execute(sql)
print('查询的结果有%s条数据'%count)
# 获取第一行
dateOne = cur.fetchone()
print(dateOne)
# 向上移动一行
cur.scroll(-1)
# 向下移动一行
cur.scroll(1)
cur.scroll(1,mode='absolute') 绝对的，这里指的是第一行
cur.scroll(1,mode='relative') 相对的
#获取所有行的数据
dataAll = cur.fetchall()
print(dataAll)
for temp in dataAll:
print(temp)
print(dataAll[-1][2]) #dataAll[-1]得到的是一个用户所有的信息，dataAll[-1][2]获取最后一个人的密码
for temp in cur:
print(temp)
s = 'id:%s,name:%s,pwd:%s,birthday:%s'
for temp in dataAll:
print(s%(temp[0],temp[1],temp[2],temp[3]))
# 关闭
cur.close()
conn.close()
4.对象的属性
1.增
#encoding=utf-8import pymysqltry: conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8') cs1=conn.cursor() count=cs1.execute("insert into students(sname) values('张良')") print(count) conn.commit() cs1.close() conn.close()except Exception,e: print(e)
import pymysql
try:
conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8')
cs1=conn.cursor()
count=cs1.execute("insert into students(sname) values('张良')")
print(count)
conn.commit()
cs1.close()
conn.close()
except Exception,e:
print(e)
2.修改
#encoding=utf-8import pymysqltry: conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8') cs1=conn.cursor() count=cs1.execute("update students set sname='刘邦' where id=6") print(count) conn.commit() cs1.close() conn.close()except Exception,e: print(e)
import pymysql
try:
conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8')
cs1=conn.cursor()
count=cs1.execute("update students set sname='刘邦' where id=6")
print(count)
conn.commit()
cs1.close()
conn.close()
except Exception,e:
print(e)
3.删除
#encoding=utf-8import pymysqltry: conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8') cs1=conn.cursor() count=cs1.execute("delete from students where id=6") print(count) conn.commit() cs1.close() conn.close()except Exception as e: print(e)
import pymysql
try:
conn=pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8')
cs1=conn.cursor()
count=cs1.execute("delete from students where id=6")
print(count)
conn.commit()
cs1.close()
conn.close()
except Exception as e:
print(e)
4.查
import Pymysqltry: conn=Pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8') cur=conn.cursor() cur.execute('select * from students where id=7') result=cur.fetchone() print result cur.close() conn.close()except Exception as e: print(e)
try:
conn=Pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8')
cur=conn.cursor()
cur.execute('select * from students where id=7')
result=cur.fetchone()
print result
cur.close()
conn.close()
except Exception as e:
print(e)
#encoding=utf8import Pymysqltry: conn=Pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8') cur=conn.cursor() cur.execute('select * from students') result=cur.fetchall() print result cur.close() conn.close()except Exception as e: print(e)
import Pymysql
try:
conn=Pymysql.connect(host='localhost',port=3306,db='test1',user='root',passwd='mysql',charset='utf8')
cur=conn.cursor()
cur.execute('select * from students')
result=cur.fetchall()
print result
cur.close()
conn.close()
except Exception as e:
print(e)
实例一：参数
# 导入python操作mysql的模块import pymysqlimport time# 获取连接对象conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')# 获取执行工具cur = conn.cursor()# sql语句,增删改，sql注入sql = 'insert into t_user(name,pwd,birthday) values(%s,%s,%s)'# 参数列表name = input('输入姓名:')pwd = input('输入密码:')birthday = input('输入生日:') # 2017年10月01日-->日期struct_time(--->2017-10-01)birthday = time.strptime(birthday,'%Y年%m月%d日') #这里我们就用到了时间与字符串的相互转换(详情见MySQL高级)params = [name,pwd,birthday]# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数count = cur.execute(sql,params)#提交conn.commit()print('受影响的行数:%s'%count)# 关闭cur.close()conn.close()
import pymysql
import time
# 获取连接对象
conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')
# 获取执行工具
cur = conn.cursor()
# sql语句,增删改，sql注入
sql = 'insert into t_user(name,pwd,birthday) values(%s,%s,%s)'
# 参数列表
name = input('输入姓名:')
pwd = input('输入密码:')
birthday = input('输入生日:') # 2017年10月01日-->日期struct_time(--->2017-10-01)
birthday = time.strptime(birthday,'%Y年%m月%d日') #这里我们就用到了时间与字符串的相互转换(详情见MySQL高级)
params = [name,pwd,birthday]
# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数
count = cur.execute(sql,params)
#提交
conn.commit()
print('受影响的行数:%s'%count)
# 关闭
cur.close()
conn.close()
实例二：抛出异常
# 导入python操作mysql的模块import pymysqltry: conn = None cur = None # 获取连接对象 conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8') # 模拟异常 # a = 1 / 0 # 获取执行工具 cur = conn.cursor() # sql语句,增删改 sql = 'insert into t_user(name,pwd,birthday) values("小伊","123456",str_to_date("2017年10月20日","%Y年%m月%d日"))' # 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数 count = cur.execute(sql) # 提交 conn.commit() print('受影响的行数:%s' % count)except Exception as ex: # 打印异常信息，测试时候使用，项目上线，去掉 print(str(ex)) # 将异常继续抛出 # raisefinally: if cur != None: cur.close() if conn != None: conn.close()
import pymysql
try:
conn = None
cur = None
# 获取连接对象
conn = pymysql.connect(host='127.0.0.1',
user='root',
password='123456',
database='python01',
port=3306,
charset='utf8')
# 模拟异常
# a = 1 / 0
# 获取执行工具
cur = conn.cursor()
# sql语句,增删改
sql = 'insert into t_user(name,pwd,birthday) values("小伊","123456",str_to_date("2017年10月20日","%Y年%m月%d日"))'
# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数
count = cur.execute(sql)
# 提交
conn.commit()
print('受影响的行数:%s' % count)
except Exception as ex:
# 打印异常信息，测试时候使用，项目上线，去掉
print(str(ex))
# 将异常继续抛出
# raise
finally:
if cur != None:
cur.close()
if conn != None:
conn.close()
实例三：
# 导入python操作mysql的模块import pymysql# 获取连接对象conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')# 获取执行工具cur = conn.cursor()# sql语句,增删改#sql = 'select birthday from t_user'sql = 'select id,name,pwd,birthday from t_user'# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数count = cur.execute(sql)print('查询的结果有%s条数据'%count)# 获取第一行# dateOne = cur.fetchone()# print(dateOne)# for temp in cur:# print(temp)s = 'id:%s,name:%s,pwd:%s,birthday:%s'for temp in dataAll: print(s%(temp[0],temp[1],temp[2],temp[3]))# 关闭cur.close()conn.close()
import pymysql
# 获取连接对象
conn = pymysql.connect(host='127.0.0.1', user='root', password='123456', database='python01', port=3306, charset='utf8')
# 获取执行工具
cur = conn.cursor()
# sql语句,增删改
#sql = 'select birthday from t_user'
sql = 'select id,name,pwd,birthday from t_user'
# 执行,返回值。如果是增删改，返回受影响的行数，如果是查询，返回查询的行数
count = cur.execute(sql)
print('查询的结果有%s条数据'%count)
# 获取第一行
# dateOne = cur.fetchone()
# print(dateOne)
# for temp in cur:
# print(temp)
s = 'id:%s,name:%s,pwd:%s,birthday:%s'
for temp in dataAll:
print(s%(temp[0],temp[1],temp[2],temp[3]))
# 关闭
cur.close()
conn.close()我们可以封装一个py文件，方便每次进行调用。把这个库定义为：mySqlHelper
"""python操作mysql进行增删改查的封装1、增删改，代码类似2、查询代码分析1、获取连接对象2、sql语句不同，参数不同3、获取执行对象"""import pymysqlclass MysqlHelper: '''python操作mysql的增删改查的封装''' def __init__(self, host, user, password, database, port=3306, charset='utf8'): ''' 初始化参数 :param host: 主机 :param user: 用户名 :param password: 密码 :param database: 数据库 :param port: 端口号，默认是3306 :param charset: 编码，默认是utf8 ''' self.host = host self.port = port self.database = database self.user = user self.password = password self.charset = charset def connect(self): ''' 获取连接对象和执行对象 :return: ''' self.conn = pymysql.connect(host=self.host, user=self.user, password=self.password, database=self.database, port=self.port, charset=self.charset) self.cur = self.conn.cursor() def fetchone(self, sql, params=None): ''' 根据sql和参数获取一行数据 :param sql: sql语句 :param params: sql语句对象的参数元组，默认值为None :return: 查询的一行数据 ''' dataOne = None try: count = self.cur.execute(sql, params) if count != 0: dataOne = self.cur.fetchone() except Exception as ex: print(ex) finally: self.close() return dataOne def fetchall(self, sql, params=None): ''' 根据sql和参数获取一行数据 :param sql: sql语句 :param params: sql语句对象的参数列表，默认值为None :return: 查询的一行数据 ''' dataall = None try: count = self.cur.execute(sql, params) if count != 0: dataall = self.cur.fetchall() except Exception as ex: print(ex) finally: self.close() return dataall def __item(self, sql, params=None): ''' 执行增删改 :param sql: sql语句 :param params: sql语句对象的参数列表，默认值为None :return: 受影响的行数 ''' count = 0 try: count = self.cur.execute(sql, params) self.conn.commit() except Exception as ex: print(ex) finally: self.close() return count def update(self, sql, params=None): ''' 执行修改 :param sql: sql语句 :param params: sql语句对象的参数列表，默认值为None :return: 受影响的行数 ''' return self.__item(sql, params) def insert(self, sql, params=None): ''' 执行新增 :param sql: sql语句 :param params: sql语句对象的参数列表，默认值为None :return: 受影响的行数 ''' return self.__item(sql, params) def delete(self, sql, params=None): ''' 执行删除 :param sql: sql语句 :param params: sql语句对象的参数列表，默认值为None :return: 受影响的行数 ''' return self.__item(sql, params) def close(self): ''' 关闭执行工具和连接对象 ''' if self.cur != None: self.cur.close() if self.conn != None: self.conn.close()
import pymysql
class MysqlHelper:
'''python操作mysql的增删改查的封装'''
def __init__(self, host, user, password, database, port=3306, charset='utf8'):
'''
初始化参数
:param host: 主机
:param user: 用户名
:param password: 密码
:param database: 数据库
:param port: 端口号，默认是3306
:param charset: 编码，默认是utf8
'''
self.host = host
self.port = port
self.database = database
self.user = user
self.password = password
self.charset = charset
def connect(self):
'''
获取连接对象和执行对象
:return:
'''
self.conn = pymysql.connect(host=self.host,
user=self.user,
password=self.password,
database=self.database,
port=self.port,
charset=self.charset)
self.cur = self.conn.cursor()
def fetchone(self, sql, params=None):
'''
根据sql和参数获取一行数据
:param sql: sql语句
:param params: sql语句对象的参数元组，默认值为None
:return: 查询的一行数据
'''
dataOne = None
try:
count = self.cur.execute(sql, params)
if count != 0:
dataOne = self.cur.fetchone()
except Exception as ex:
print(ex)
finally:
self.close()
return dataOne
def fetchall(self, sql, params=None):
'''
根据sql和参数获取一行数据
:param sql: sql语句
:param params: sql语句对象的参数列表，默认值为None
:return: 查询的一行数据
'''
dataall = None
try:
count = self.cur.execute(sql, params)
if count != 0:
dataall = self.cur.fetchall()
except Exception as ex:
print(ex)
finally:
self.close()
return dataall
def __item(self, sql, params=None):
'''
执行增删改
:param sql: sql语句
:param params: sql语句对象的参数列表，默认值为None
:return: 受影响的行数
'''
count = 0
try:
count = self.cur.execute(sql, params)
self.conn.commit()
except Exception as ex:
print(ex)
finally:
self.close()
return count
def update(self, sql, params=None):
'''
执行修改
:param sql: sql语句
:param params: sql语句对象的参数列表，默认值为None
:return: 受影响的行数
'''
return self.__item(sql, params)
def insert(self, sql, params=None):
'''
执行新增
:param sql: sql语句
:param params: sql语句对象的参数列表，默认值为None
:return: 受影响的行数
'''
return self.__item(sql, params)
def delete(self, sql, params=None):
'''
执行删除
:param sql: sql语句
:param params: sql语句对象的参数列表，默认值为None
:return: 受影响的行数
'''
return self.__item(sql, params)
def close(self):
'''
关闭执行工具和连接对象
'''
if self.cur != None:
self.cur.close()
if self.conn != None:
self.conn.close()
1.测试查询多条数据
import mysqlHelper# 初始化对象helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')# 连接helper.connect()# sqlsql = 'select * from t_user where name = %s and id > %s'# paramsparams = ['小茗',1]# 执行data = helper.fetchall(sql, params)# 判断if data: for temp in data: print(temp)else: # None,False,0 print('没有数据.')helper.close()
# 初始化对象
helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')
# 连接
helper.connect()
# sql
sql = 'select * from t_user where name = %s and id > %s'
# params
params = ['小茗',1]
# 执行
data = helper.fetchall(sql, params)
# 判断
if data:
for temp in data:
print(temp)
else: # None,False,0
print('没有数据.')
helper.close()
2.测试查询一条数据
import mysqlHelper# 初始化对象helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')# 连接helper.connect()# sqlsql = 'select * from t_user where id = %s'#sql = 'select * from t_user where id = 1'# paramsparams = [2]# 执行data = helper.fetchone(sql, params)#data = helper.fetchone(sql)# 判断if data: print(data)else: # None,False,0 print('没有数据.')
# 初始化对象
helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')
# 连接
helper.connect()
# sql
sql = 'select * from t_user where id = %s'
#sql = 'select * from t_user where id = 1'
# params
params = [2]
# 执行
data = helper.fetchone(sql, params)
#data = helper.fetchone(sql)
# 判断
if data:
print(data)
else: # None,False,0
print('没有数据.')
3.测试增删改
import mysqlHelperimport time# 初始化对象helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')# 连接helper.connect()# sqlsql = 'update t_user set name =%s,pwd=%s,birthday=%s where id=%s'# paramsid = input('输入编号:')name = input('输入姓名:')pwd = input('输入密码:')birthday = time.strptime(input('输入生日:'), '%Y年%m月%d日')params = [name, pwd, birthday,id]# 执行count = helper.update(sql, params)# 判断if count: print('操作成功.')else: # None,False,0 print('操作失败.')
# 初始化对象
helper = mysqlHelper.MysqlHelper('127.0.0.1', 'root', '123456', 'python01')
# 连接
helper.connect()
# sql
sql = 'update t_user set name =%s,pwd=%s,birthday=%s where id=%s'
# params
id = input('输入编号:')
name = input('输入姓名:')
pwd = input('输入密码:')
birthday = time.strptime(input('输入生日:'), '%Y年%m月%d日')
params = [name, pwd, birthday,id]
# 执行
count = helper.update(sql, params)
# 判断
if count:
print('操作成功.')
else: # None,False,0
print('操作失败.')
4.简单的登录和注册
做项目的时候会有个尝试登录和注册的时候需要对密码进行加密进行存储，刚好结合sql语句进行一个简单的交互。
注意：
create table userinfos( id int primary key auto_increment, uname varchar(20), upwd char(40), isdelete bit default 0);/*ret = doPwd('123')print(ret)结果：40bd001563085fc35165329ea1ff5c5ecbdbbeef */-- 插入如下数据，用户名为123,密码为123,这是sha1加密后的值insert into userinfos values(1,'123','40bd001563085fc35165329ea1ff5c5ecbdbbeef',0);table userinfos(
id int primary key auto_increment,
uname varchar(20),
upwd char(40),
isdelete bit default 0
);
/*
ret = doPwd('123')
print(ret)
结果：40bd001563085fc35165329ea1ff5c5ecbdbbeef
*/
-- 插入如下数据，用户名为123,密码为123,这是sha1加密后的值
insert into userinfos
values(1,'123','40bd001563085fc35165329ea1ff5c5ecbdbbeef',0);
登录与注册
import hashlibfrom mysqlHelper import MysqlHelperdef login(): '''登录''' name = input('输入用户名:') pwd = input('输入密码:') #加密 pwd = doPwd(pwd) helper = MysqlHelper('127.0.0.1', 'root', '123456', 'python01') helper.connect() sql = 'select * from t_user where name=%s and pwd=%s' params = [name, pwd] data = helper.fetchone(sql, params) if data: print('登录成功.') else: # None,False,0 print('登录失败.')def doPwd(pwd): '''sha1编码''' mysha1 = hashlib.sha1() mysha1.update(pwd.encode('utf-8')) pwd = mysha1.hexdigest() return pwddef register(): '''注册''' name = input('输入用户名:') pwd = input('输入密码:') # 加密 pwd = doPwd(pwd) helper = MysqlHelper('127.0.0.1', 'root', '123456', 'python01') helper.connect() sql = 'insert into t_user(name,pwd) values(%s,%s)' params = [name, pwd] count = helper.insert(sql, params) if count: print('操作成功.') else: # None,False,0 print('操作失败.')if __name__ == '__main__': #register() login()
from mysqlHelper import MysqlHelper
def login():
'''登录'''
name = input('输入用户名:')
pwd = input('输入密码:')
#加密
pwd = doPwd(pwd)
helper = MysqlHelper('127.0.0.1', 'root', '123456', 'python01')
helper.connect()
sql = 'select * from t_user where name=%s and pwd=%s'
params = [name, pwd]
data = helper.fetchone(sql, params)
if data:
print('登录成功.')
else: # None,False,0
print('登录失败.')
def doPwd(pwd):
'''sha1编码'''
mysha1 = hashlib.sha1()
mysha1.update(pwd.encode('utf-8'))
pwd = mysha1.hexdigest()
return pwd
def register():
'''注册'''
name = input('输入用户名:')
pwd = input('输入密码:')
# 加密
pwd = doPwd(pwd)
helper = MysqlHelper('127.0.0.1', 'root', '123456', 'python01')
helper.connect()
sql = 'insert into t_user(name,pwd) values(%s,%s)'
params = [name, pwd]
count = helper.insert(sql, params)
if count:
print('操作成功.')
else: # None,False,0
print('操作失败.')
if __name__ == '__main__':
#register()
login()
实际项目中的登录注册往往加入了各种验证，这里的代码只是一个简单的登录注册，只为了学习交流。
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