python学习笔记（七）操作mysql

python操作mysql数据库需要先安装pymysql模块，在之前博客中可翻看如何安装，最简单的就是pip install pymysql

1.导入pymysql模块   import pymysql

2.连接数据库，需要ip，账号，密码，端口号，数据库等信息

3.建立游标

4.执行sql语句

5.获取结果

6.关闭游标

7.关闭连接

import pymysql
coon = pymysql.connect(host='192.168.21.129',user='root',passwd='123456',port=3306,db='test',charset='utf8')
cur = coon.cursor()
sql = 'select * from user'
cur.execute(sql)
res = cur.fetchall()
print(res)
cur.close()
coon.close()

import pymysql
coon = pymysql.connect(host='192.168.21.129',user='root',passwd='123456',port=3306,db='test',charset='utf8')
cur = coon.cursor()  #建立游标
cur.execute('insert into user(username,passwd) VALUE ("2222","4444");')  #执行sql
coon.commit()  #delete update insert必须得coomit
cur.close()    #关闭游标
coon.close()   #关闭连接

 在执行select语句和delete  update  insert 语句不一样，那我们可以定义一个函数，在函数中用条件来判断sql语句

def my_db(host,user,passwd,db,sql,port=3306,charset='utf8'):
    import pymysql
    coon = pymysql.connect(user=user,
                           host=host,
                           port=port,
                           passwd=passwd,
                           db=db,
                           charset=charset
                           )
    cur = coon.cursor() #建立游标
    cur.execute(sql)#执行sql
    if sql.strip()[:6].upper()=='SELECT':   #sql语句切片取前6位，然后转换为大写字母，再进行比较
        res =  cur.fetchall()
    else:
        coon.commit()
        res = 'ok'
    cur.close()
    coon.close()
    return res