Python3 pymysql 访问MySql数据库

Posted 2021-01-08 ygzhaof_100

使用pymysql来访问MySQL数据库，注意，有些使用PyMySQL，Python2是mysqldb

 

如没该module则安装：pip install pymysql

（本人Java转Python，还有java编写习惯，有错误请及时提出，相互交流）

1、定义获取数据库连接的Module，

 DataBase.py

import pymysql

class MySQLDB:
    __config={
    ‘host‘ : ‘127.0.0.1‘,
    ‘port‘ : 3306,
    ‘user‘ : ‘root‘,
    ‘password‘ : ‘admin‘,
    ‘db‘ : ‘test‘,
    ‘charset‘ : ‘utf8‘
    }
    #定义了静态方法，类名可直接打点调用
    @staticmethod
    def getConn():
        connection = pymysql.connect(**MySQLDB.__config)
        return connection

2、EmpDao.py 访问数据DAO层

 1 from dataBase import DataBase
 2 from dataBase import Entity
 3  
 4 class EmpDao:
 5     ‘‘‘
 6     emp表的DAO
 7     ‘‘‘
 8     def saveEmp(self,empEntity):
 9         """
10         保存
11         """
12         try:
13             self.connection=DataBase.MySQLDB.getConn();#获取数据库连接
14             with self.connection.cursor() as cursor: #获取游标
15                 sql = ‘INSERT INTO emp (empno,ename,mgr,job,hiredate,sal,comm,deptno) VALUES (%s, %s, %s, %s, %s,%s,%s,%s)‘
16                 cursor.execute(sql, empEntity) #执行SQL
17                 self.connection.commit() #提交事务
18         except Exception as e:
19             print(e) #打印异常
20         finally:
21             self.connection.close()#关闭数据库连接
22 
23 
24     def selectEmp(self,sqlParam):
25         """
26         条件查询
27         """
28         try:
29             self.connection = DataBase.MySQLDB.getConn();
30             with self.connection.cursor() as cursor:
31                 sql=‘select empno,ename,job,mgr,sal,comm,hiredate,deptno from emp where 1=1  ‘
32                 if sqlParam:
33                     sql=sql+‘ %s ‘%(sqlParam) #插入条件sql片段
34                 print(sql)
35                 cursor.execute(sql)
36                 self.rows = cursor.fetchall()#抓取行数据  
37         except Exception as e:
38              print(e)
39         finally:
40             self.connection.close()
41         return self.rows
42 
43 
44     def selectRowCount(self,sqlParam):
45         """
46         查询总记录数
47         """
48         try:
49             self.connection=DataBase.MySQLDB.getConn()
50             with self.connection.cursor() as cursor:
51                 sql=‘select count(empno) from emp where 1=1 ‘
52                 if sqlParam:
53                     sql=sql+‘%s‘%(sqlParam)#sql条件片段
54                 print(sql)
55                 cursor.execute(sql)
56                 self.rows=cursor.fetchall()
57         except Exception as e:
58             print(e)
59         finally:
60             self.connection.close()
61         return self.rows[0][0]
62 
63 
64     def selectRowsPaper(self,sqlParam=None,pageNow=1,pageSize=5):
65         """
66         分页查询
67         """
68         self.pageNow=pageNow
69         self.pageSize=pageSize
70         self.offset=(self.pageNow-1)*self.pageSize #偏移量
71         self.total=self.selectRowCount(sqlParam)#总记录数
72         #总页数
73         self.totalPage= int(self.total/self.pageSize)  if self.total%self.pageSize==0 else int(self.total/self.pageSize) +1
74 
75         try:
76             self.connection = DataBase.MySQLDB.getConn()
77             with self.connection.cursor() as cursor:
78                 sql = ‘select  empno,ename,job,mgr,sal,comm,hiredate,deptno from emp where 1=1 ‘
79                 if sqlParam:
80                     sql = sql + ‘%s‘ % (sqlParam)
81                 sql=sql+‘ limit %s,%s‘%(self.offset,self.pageSize)
82                 print(sql)
83                 cursor.execute(sql)
84                 self.rows = cursor.fetchall()
85                 return {‘total‘:self.total,‘pageNow‘:self.pageNow,‘totalPage‘:self.totalPage,‘rows‘:self.rows}
86         except Exception as e:
87             print(e)

3、测试

（1）新增

1 if __name__ == ‘__main__‘:
2     empDao =EmpDao()
3     empDao.saveEmp((116, ‘ZYG‘, 7989, ‘Teacher‘, ‘1999-10-10‘, 23000, None, 20))

（2）分页查询

if __name__ == ‘__main__‘:
    empDao =EmpDao()
    #分页查询
    res=empDao.selectRowsPaper(pageNow=2)
    print(res)
    s=res[‘rows‘]
    for r in s:
        print(‘编号：%s,姓名:%s,入职日期：%s,工资：%s,部门：%s‘ % (r[0], r[1], r[6], r[4], r[7]))