python开发mysql:Pymysql模块

pymysql模块的使用

 #1 基本使用
 # import pymysql
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4')  # 链接
 # cursor=conn.cursor() #拿到游标，即mysql >，接收命令
 # sql='select * from userinfo where id>1;'
 # rows=cursor.execute(sql) #提交命令，拿到受影响的行数
 # print('%s rows in set (0.00 sec)' %rows)
 # cursor.close()
 # conn.close()

 #2 小练习
 # import pymysql
 # user=input('用户名>>: ').strip()
 # pwd=input('密码>>: ').strip()
 # #链接，拿到游标
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4')
 # cursor=conn.cursor() #拿到游标，即mysql >
 # #执行sql
 # sql='select * from userinfo where user="%s" and pwd="%s";' %(user,pwd)
 # print(sql)
 # rows=cursor.execute(sql) #拿到受影响的行数
 # print('%s rows in set (0.00 sec)' %rows)
 # cursor.close()
 # conn.close()
 # if rows:
 #     print('登录成功')
 # else:
 #     print('登录失败')

 #** 上面有sql注入，‘select * from user where user="%s" and password="%s"’;%(user,pwd)
 # user>>egon" -- hahahaha  这里--"粘起来就会报错，必须有空格才能跳过密码，因为strip的原因，所以后面有内容
 # select * from user where user="egon" -- hahahaha" and password="%s"’
 # user>> xxx" or 1=1 -- hahaha
 # select * from user where user="xxx" or 1=1 -- hahaha" -- hahahaha" and password="%s"’ 用户名密码都不需要要

 #3:解决sql注入
 # import pymysql
 # user=input('用户名>>: ').strip()
 # pwd=input('密码>>: ').strip()
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4')
 # cursor=conn.cursor()
 #
 # sql='select * from userinfo where user=%s and pwd=%s;'
 # rows=cursor.execute(sql,[user,pwd])  #就是将双引号去除了
 # print('%s rows in set (0.00 sec)' %rows)
 # cursor.close()
 # conn.close()
 # if rows:
 #     print('登录成功')
 # else:
 #     print('登录失败')

 #4 增删改
 # import pymysql
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4',charset='utf8')#注意字符编码默认是latin
 # cursor=conn.cursor()
 # sql='insert into userinfo(user,pwd) values(%s,%s);'
 # # rows=cursor.execute(sql,('alex','456')) #提交命令
 # rows=cursor.executemany(sql,[('yuanhao','123'),('laowu','123'),('kgf','12323')]) #提交多组命令
 # print('%s row in set (0.00 sec)' %rows)
 # conn.commit()  #执行命令
 # cursor.close()
 # conn.close()

 #5 查:fetchone,fetchmany,fetchall
 # import pymysql
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4',charset='utf8')
 # cursor=conn.cursor()
 # sql='select * from userinfo;'
 # rows=cursor.execute(sql)

 #5.1查单条，返回的是元祖
 # res1=cursor.fetchone()
 # res2=cursor.fetchone()
 # res3=cursor.fetchone()
 # print(res1[0])
 # print(res2)
 # print(res3)

 #5.2查多条
 # print(cursor.fetchmany(3)) #显示在一个大元祖里
 # print(cursor.fetchone())

 #5.3查所有
 # print(cursor.fetchall()) #显示在一个大元祖里
 # print(cursor.fetchone()) #None

 #5.4光标的移动，绝对路径
 # print(cursor.fetchall())
 # print(cursor.fetchone())
 # cursor.scroll(1,mode='absolute')
 # print(cursor.fetchone())
 # cursor.scroll(3,mode='absolute')
 # print(cursor.fetchone())

 #5.5相对路径
 # print(cursor.fetchone())
 # print(cursor.fetchone())
 # cursor.scroll(-2,mode='relative')
 # print(cursor.fetchone())

 # cursor.close()
 # conn.close()

 #6 查看当前光标ID,用于多表关联，插入ID时候，其他表可以获取这个ID递增
 # import pymysql
 # conn=pymysql.connect(host='localhost',user='root',password='123',database='db4',charset='utf8')
 # cursor=conn.cursor()
 # sql='insert into userinfo(user,pwd) values(%s,%s);'
 # rows=cursor.execute(sql,('alex阿什顿发','123'))
 # conn.commit()
 # print(cursor.lastrowid)
 # cursor.close()
 # conn.close()