视图、触发器、事务、存储过程、函数、数据备份与恢复、流程控制

create table student(
  s_id int(3),
  name varchar(20),
  math float,
  chinese float
);
insert into student values(1,'tom',80,70),(2,'jack',80,80),(3,'rose',60,75);

create table stu_info(
  s_id int(3),
  class varchar(50),
  address varchar(100)
);
insert into stu_info values(1,'二班','安徽'),(2,'二班','湖南'),(3,'三班','黑龙江');

#创建视图包括 编号 学生的姓名和班级
create view stu_view (编号,姓名,班级) as select student.s_id,student.name,stu_info.class from student,stu_info where student.s_id=stu_info.s_id;
#查询视图
select * from stu_view;

create table salary_info(
id int primary key,
name char(10),
salary double,
dept char(10)
);
insert into salary_info values
(1,"刘强东",900000,"市场"),
(2,"马云",800090,"市场"),
(3,"李彦宏",989090,"财务"),
(4,"马化腾",87879999,"财务");

#创建市场部视图
create view info as select * from salary_info where dept='市场';
#查看市场部视图
select * from info;

create table blog(id int primary key auto_increment,content text,b_id int,foreign key(b_id) references blog(id),update_time timestamp);
create table blogs(id int primary key auto_increment,content text,b_id int,foreign key(b_id) references blog(id),update_time timestamp);

创建触发器
delimiter //
create trigger t1 after update on blog for each row
begin
insert into update_log  values(null,new.content,now(),new.id);
end //
delimiter ;
#查询数据
select *from users;

CREATE TABLE cmd (
    id INT PRIMARY KEY auto_increment,
    USER CHAR (32),
    priv CHAR (10),
    cmd CHAR (64),
    sub_time datetime, #提交时间
    success enum ('yes', 'no') #0代表执行失败
);
#错误日志表
CREATE TABLE errlog (
    id INT PRIMARY KEY auto_increment,
    err_cmd CHAR (64),
    err_time datetime
);

delimiter //
create trigger trigger1 after insert on cmd for each row
begin
if new.success = "no" then
   insert into errlog values(null,new.cmd,new.sub_time);
end if;
end//
delimiter ;

INSERT INTO cmd (
    USER,
    priv,
    cmd,
    sub_time,
    success
)
VALUES
    ('jerry','0755','ls -l /etc',NOW(),'yes'),
    ('jerry','0755','cat /etc/passwd',NOW(),'no'),
    ('jerry','0755','useradd xxx',NOW(),'no'),
    ('jerry','0755','ps aux',NOW(),'yes');

select *from errlog;

import pymysql

conn = pymysql.connect(host='127.0.0.1', user='root', password='123321', database='day45')
cursor = conn.cursor(pymysql.cursors.DictCursor)

try:
    sql1 = 'update account set money=money-100 where id=1'
    sql2 = 'update account set money=money+100 where id=2'
    cursor.execute(sql1)
    cursor.execute(sql2)
    conn.commit()
    print('转账成功！')
except Exception as e:
    print(type(e), e)
    # cursor.scroll()#发生错误就回滚

create procedure p1(type 参数名 数据类型)
type ：in 输入参数 out输出参数 inout既能输出又能输入
delimiter //
create procedure p1(in a double,in b double)
begin
select *from account where money >= a and  money <= b;
end//
delimiter ;

delimiter //
create procedure p2(in a double,in b double,out res char(20))
begin
        select *from account where money >= a and  money <= b;
        set res = "success";
end//
delimiter ;

#删除
drop procedure 过程名称;
#查看所有 
select `name` from mysql.proc where db = 'db02' and `type` = 'PROCEDURE';

create table student(
  s_id int(3),
  name varchar(20),
  math float,
  chinese float
);
insert into student values(1,'tom',80,70),(2,'jack',80,80),(3,'rose',60,75);

create table stu_info(
  s_id int(3),
  class varchar(50),
  address varchar(100)
);
insert into stu_info values(1,'二班','安徽'),(2,'二班','湖南'),(3,'三班','黑龙江');

delimiter //
create procedure p1(in m int,in n int,out res int)
begin
    select *from student where chinese > m and chinese < n;
    #select *from student where chineseXXX > m and chinese < n; 修改错误的列名以测试执行失败
    set res = 100;
end//
delimiter ;

#调用存储过程
call p1(70,80,@res);
#查看执行结果
select @res;

import  pymysql
#建立连接
conn = pymysql.connect(
    host="127.0.0.1",
    user="root",
    password="admin",
    database="db02"
)
# 获取游标
cursor = conn.cursor(pymysql.cursors.DictCursor)

# 调用用存储过程
cursor.callproc("p1",(70,80,0)) #p1为存储过程名 会自动为为每个值设置变量,名称为 @_p1_0,@_p1_1,@_p1_2
# 提取执行结果时否有结果取决于存储过程中的sql语句
print(cursor.fetchall())
# 获取执行状态
cursor.execute("select @_p1_2")
print(cursor.fetchone())

delimiter //
create PROCEDURE p5(OUT p_return_code char(20))
BEGIN 
    DECLARE exit handler for sqlexception 
    BEGIN 
        # ERROR 
        set p_return_code = "出现异常,回滚!"; 
        rollback; 
    END; 
    # exit 也可以换成continue 表示发生异常时继续执行
    DECLARE exit handler for sqlwarning 
    BEGIN 
        # WARNING 
        set p_return_code = "出现警告,回滚!";
        rollback; 
    END; 

    START TRANSACTION; 
    update account set money = money - 1000 where id = 1;
    update account set money = money - 1000 where id = 1; # moneys字段导致异常
    COMMIT; 

    # SUCCESS 
    set p_return_code = 0; #0代表执行成功
END //
delimiter ;

#在mysql中调用存储过程
call p5(@res);
select @res;

import pymysql

conn = pymysql.connect(host='127.0.0.1', user='root', password='123321', database='day45')
cursor = conn.cursor(pymysql.cursors.DictCursor)

# 调用存储过程 如果是一个输出out参数 随便给个值就行
# cursor.callproc('p2',(500,2000,0))
# # pymysql会自动定义变量@_存储过程名称_参数索引
# #分别是：@_p2_0  @_p2_1  @_p2_2
#
# # 获取结果
# # print(cursor.fetchall())
# # # 获取存储过程的结果
# # cursor.execute('select @_p2_2')
# # print(cursor.fetchall())

# 调用
cursor.callproc('p5',(0,))
# 获取结果是否有结果取决于存储过程中是否select语句
print(cursor.fetchall())
# 通过查询变量获取执行状态
cursor.execute('select @_p5_0')
print(cursor.fetchall())

#语法
CREATE FUNCTION f_name(paramters)
returns dataType;
return value;

create function addfuntion(a int,b int)
returns int return a + b;
54asd#执行函数
select addfuntion(1,1);