mysql之视图存储过程触发器约束授权

Posted 2021-01-11 拼命姑娘fh

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了mysql之视图存储过程触发器约束授权相关的知识，希望对你有一定的参考价值。

视图：
     简单视图：单张表
     复杂视图：多张，子查询
     物化视图：

MariaDB [hidb]> create view v1_students as select name,age from students;

MariaDB [hellodb]> create view v3_students as select name,age from students where age>40 ;
Query OK, 0 rows affected (0.05 sec)

MariaDB [hellodb]> update v3_students set age=39 where age>40;
Query OK, 3 rows affected (0.14 sec)
Rows matched: 3 Changed: 3 Warnings: 0

MariaDB [hellodb]> select * from v3_students;
Empty set (0.00 sec)

注意：视图存放的不是数据，而是select语句，修改视图相当于修改基表，如果修改完之后，不满足创建视图时候的条件时，再次查询视图就会为空，因为表里的数据已被修改。这时，需要加with check option
MariaDB [hidb]> create view v3_students as select name,age from students where age > 40 with check option;

MariaDB [hidb]> show create view v3_studentsG;
*************************** 1. row ***************************
View: v3_students
Create View: CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v3_students` AS select `students`.`Name` AS `name`,`students`.`Age` AS `age` from `students` where (`students`.`Age` > 40) WITH CASCADED CHECK OPTION
character_set_client: utf8
collation_connection: utf8_general_ci
1 row in set (0.00 sec)

MariaDB [hellodb]> select * from v3_students;
+-------------+-----+
| name | age |
+-------------+-----+
| An Qila | 53 |
| Huang Zhong | 46 |
| Sun Wukong | 250 |
+-------------+-----+
3 rows in set (0.13 sec)

MariaDB [hellodb]> update v3_students set age=39 where age>40;
ERROR 1369 (44000): CHECK OPTION failed `hellodb`.`v3_students`

复杂视图：
MariaDB [hidb]> create view v4_students as select s.name student_name,t.name teacher_name from students s join teachers t on s.teacherid=t.tid;

MariaDB [hidb]> update v4_students set teacher_name=‘Tie Muzhen‘ where student_name=‘da ji‘;

MariaDB [hidb]> create view v5_students as select classid,count(stuid) student_count from students group by classid having classid is not null;
Query OK, 0 rows affected (0.01 sec)

MariaDB [hidb]> select * from v5_students;
+---------+---------------+
| classid | student_count |
+---------+---------------+
|       1 |             4 |
|       2 |             3 |
|       3 |             4 |
|       4 |             4 |
|       5 |             1 |
|       6 |             4 |
|       7 |             3 |
+---------+---------------+
7 rows in set (0.01 sec)

MariaDB [hidb]> update v5_students set student_count=10 where classid=7;
ERROR 1288 (HY000): The target table v5_students of the UPDATE is not updatable

注意：select 语句中包含group by时候不能修改视图中的数据，基表中没有相关信息，所以会报错。

关于视图的总结

不能修改数据的视图：

1.select 子句中包括distinct
2.select 子句中包含组函数
3.select 子句中包含group by
4.select 子句中包含union

查看创建指定的视图信息
MariaDB [hidb]> show create view v3_studentsG;

显示某视图的状态信息

MariaDB [hellodb]> show table status like ‘view_students‘G;

查看所有的视图信息
MariaDB [hidb]> select * from information_schema.viewsG;

删除视图

MariaDB [hidb]> drop view v1_students;

自定义函数

所有的自定义函数保存在mysql.proc表中，参数有多个，也可以没有，必须有且只有一个返回值。
MariaDB [mysql]> CREATE FUNCTION simpleFun() RETURNS VARCHAR(20) RETURN "Hello World!"; //不区分大小写
Query OK, 0 rows affected (0.00 sec)

MariaDB [mysql]> select simplefun();
+--------------+
| simplefun() |
+--------------+
| Hello World! |
+--------------+
1 row in set (0.00 sec)

查看所有函数的信息
MariaDB [mysql]> show function statusG;

查看指定自定义函数的定义（不能查看内置函数）
MariaDB [mysql]> show create function simplefunG;
*************************** 1. row ***************************
             Function: simplefun
             sql_mode:
      Create Function: CREATE DEFINER=`root`@`localhost` FUNCTION `simplefun`() RETURNS varchar(20) CHARSET latin1
RETURN "Hello World!"
character_set_client: utf8
collation_connection: utf8_general_ci
   Database Collation: latin1_swedish_ci
1 row in set (0.00 sec)

ERROR: No query specified

带参数的自定义函数

自定义函数里面有多语句，select语句中一旦有分号，就开始执行，与shell中函数不同的是：shell中的函数是先定义再调用，调用时候再发挥作用。所以mysql中函数也是需要预定义的，先不执行，在执行的时候用语句，里面有好多分号作用是在执行语句时候，再一行一行执行。所以修改分号的意义，先不让它执行，用其他分隔符来当执行语句的标志。
MariaDB [mysql]> delimiter //

注意：在自定义分隔符时，delimiter后面有空格
MariaDB [mysql]> CREATE FUNCTION addTwoNumber(x SMALLINT UNSIGNED, Y SMALLINT UNSIGNED)
     -> RETURNS SMALLINT BEGIN
     -> DECLARE a, b SMALLINT UNSIGNED;
     -> SET a = x, b =y;
     -> RETURN a+b;
     -> END//
Query OK, 0 rows affected (0.00 sec)
MariaDB [mysql]> delimiter ;
MariaDB [mysql]> select addtwonumber(10,20);                //调用函数
+---------------------+
| addtwonumber(10,20) |
+---------------------+
|                  30 |
+---------------------+
1 row in set (0.00 sec)

说明：局部变量的作用范围在begin…end程序中，定义的时候必须在begin…end的第一行定义

查看所有的自定义函数

MariaDB [mysql]> show function statusG;

删除自定义函数

MariaDB [mysql]> drop function simplefun2;
Query OK, 0 rows affected (0.00 sec)

存储过程

存储过程把经常使用的sql语句或业务逻辑封装起来，预编译保存在数据库中，当需要时从数据库中直接调用，省去了编译过程。提高了运行速度，降低了网络数据传输量。

所有的存储过程保存在MySQL.proc表中
查看指定的存储过程创建
show create procedure showtimeG;

查看存储过程列表

show procedure status

调用存储过程:

call showtime();

说明:当无参时,可以省略"()",当有参数时,不可省略"()”

修改存储过程

alter 语句修改存储过程只能修改存储过程的注释等无关紧要的东西，不能修改存储过程体，所以要修改存储过程，方法就是删除重建。

删除存储过程
MariaDB [mysql]> drop procedure showtime;

创建无参存储过程

MariaDB [mysql]> delimiter //
MariaDB [mysql]> create procedure showtime()
     -> begin
     -> select now();
     -> end//
Query OK, 0 rows affected (0.00 sec)

MariaDB [mysql]> delimiter ；

call showtime();

MariaDB [hellodb]> call showtime;
+---------------------+
| now() |
+---------------------+
| 2018-09-25 07:55:42 |
+---------------------+
1 row in set (0.04 sec)

Query OK, 0 rows affected (0.04 sec)

触发器trigger

触发器的执行不是由程序调用，也不是由手工启动，而是由事件来触发，激活从而来实现。

创建触发器

示例：创建触发器，在向学生表INSERT数据时，学生数增加，DELETE学生时，学生数减少
MariaDB [hellodb]> create table student_info(
-> stu_id int(11) primary key auto_increment,
-> stu_name varchar(255) default null);
Query OK, 0 rows affected (0.01 sec)

MariaDB [hellodb]> create table student_count( student_count int(11) default 0);
Query OK, 0 rows affected (0.02 sec)

Empty set (0.00 sec)

MariaDB [hellodb]> insert into student_count values (0);
Query OK, 1 row affected (0.00 sec)

MariaDB [hellodb]> select * from student_count;
+---------------+
| student_count |
+---------------+
| 0 |
+---------------+
1 row in set (0.06 sec)

MariaDB [hellodb]> create trigger trigger_student_count_insert after insert on student_info for each row update student_count set student_count=student_count+1;
Query OK, 0 rows affected (0.01 sec)

MariaDB [hellodb]> create trigger trigger_student_count_delete after delete on student_info for each row update student_count set student_count=student_count-1;
Query OK, 0 rows affected (0.01 sec)

查看trigger信息
MariaDB [hellodb]> SHOW TRIGGERSG;

触发器的结果（插入数据时候，count表中数字自加1，删除时候，减一）

MariaDB [hellodb]> insert into student_info values(1,‘liuxin‘);
Query OK, 1 row affected (0.16 sec)

MariaDB [hellodb]> select * from student_count;
+---------------+
| student_count |
+---------------+
| 1 |
+---------------+
1 row in set (0.00 sec)

MariaDB [hellodb]> delete from student_info where stu_id=1;
Query OK, 1 row affected (0.15 sec)

MariaDB [hellodb]> select * from student_count;
+---------------+
| student_count |
+---------------+
| 0 |
+---------------+
1 row in set (0.00 sec)

查询系统表information_schema.triggers的方式指定查询条件，查看指定的触发器信息。

mysql> USE information_schema;

Database changed

mysql> SELECT * FROM triggers WHERE trigger_name=‘trigger_student_count_insert‘;

删除trigger
DROP TRIGGER trigger_name;

DDL(create drop alter)

DML(insert update delete)

DQL(select)

DCL(grant revoke)

mysql 用户和权限管理

注意：用户和主机名必须一起才能表示一个账户

mysql -u root （-h localhost）默认可以不写

不同的账户

[email protected]
[email protected]
[email protected]
[email protected]

含有通配符的账户
[email protected]%.%
[email protected]%

创建帐户
MariaDB [mysql]> create user [email protected]‘192.168.40.134‘ identified by ‘centos‘;

用户重命名：

RENAME USER old_user_name TO new_user_name

MariaDB [mysql]> rename user [email protected]‘192.168.40.%‘ to [email protected]‘192.168.40.134‘;
Query OK, 0 rows affected (0.00 sec)

删除帐户（只能用root删除）

MariaDB [(none)]> drop user [email protected]‘192.168.40.134‘;

Query OK, 0 rows affected (0.06 sec)

删除默认的空用户

DROP USER ‘‘@‘localhost‘;

在centos7 上添加用户[email protected]’192.168.40.134‘，并设置密码为123

MariaDB [(none)]> create user [email protected]‘192.168.40.134‘ identified by ‘123‘;
Query OK, 0 rows affected (0.00 sec)

在centos6上输入mysql –uroot –p123 –h192.168.40.146

[[email protected] bin]#./mysql -u root -p123 -h 192.168.40.146;
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 4
Server version: 5.5.56-MariaDB MariaDB Server

Type ‘help;‘ or ‘h‘ for help. Type ‘c‘ to clear the current input statement.

注意：远程登录时，客户端地址在服务器7上，是用客户端的地址连接的，-h是服务器地址

修改密码
方法一
set password for [email protected]‘localhost‘=password("redhat");

Query OK, 0 rows affected (0.23 sec)

方法二
update mysql.user set password=password("zhongqiukuaile") where host=‘localhost‘;

此方法需要执行下面指令才能生效： mysql> FLUSH PRIVILEGES;

重置mysql管理员帐户[email protected]
vim /etc/my.cnf
[mysqld]
skip_grant_tables

重启服务：systemctl restart mariadb.service

mysql -u root 直接可免密码登录

重新设置密码时候，不能用set直接设置，因为跳过了认证。

MariaDB [(none)]> set password for [email protected]‘localhost‘=password("123");
ERROR 1290 (HY000): The MariaDB server is running with the --skip-grant-tables option so it cannot execute this statement
MariaDB [(none)]>

MariaDB [(none)]> update mysql.user set password=password("centos") where host=‘localhost‘;
Query OK, 1 row affected (0.26 sec)
Rows matched: 1 Changed: 1 Warnings: 0

再把/etc/my.cnf还原，再重启服务，完成

授权
在centos6上给centos7授权grant all on hellodb.* to [email protected]‘192.168.40.146;

MariaDB [(none)]> grant all on hellodb.* to [email protected]‘192.168.40.146‘；
Query OK, 0 rows affected (0.06 sec)

在centos7上登录到centos6上并查看授权内容

[[email protected] ~]# mysql -uroot -p123 -h 192.168.40.134
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 14
Server version: 10.2.14-MariaDB-log MariaDB Server

Type ‘help;‘ or ‘h‘ for help. Type ‘c‘ to clear the current input statement.

将某数据库下的视图授权给某用户，此用户可以修改视图，实际上修改了基表的数据，体现了视图的功能，保证了数据的安全性

MariaDB [(none)]> grant all on hellodb.view_student to [email protected]‘192.168.40.147‘;
Query OK, 0 rows affected (0.01 sec)

[[email protected] ~]# mysql -uroot -p123 -h 192.168.40.134

MariaDB [hellodb]> show tables;
+-------------------+
| Tables_in_hellodb |
+-------------------+
| view_student |
+-------------------+
1 row in set (0.00 sec)

MariaDB [hellodb]> select * from view_student;
+----------------+-----+
| student_name | sex |
+----------------+-----+3

只授权视图的查看，插入功能，除次之外，功能受限

grant select,insert on hellodb.view_student to [email protected]‘192.168.40.134;

MariaDB [hellodb]> insert into view_student values (‘ma sai‘,‘M‘);
Query OK, 1 row affected, 1 warning (0.00 sec)

MariaDB [hellodb]> update view_student set sex=‘F‘ where name=‘ma sai‘;
ERROR 1142 (42000): UPDATE command denied to user ‘root‘@‘192.168.40.134‘ for table ‘view_student‘

只授权某些字段

MariaDB [hellodb]> grant select(stuid,name,gender) on hellodb.students to [email protected]‘192.168.40.146’
Query OK, 0 rows affected (0.01 sec)

注意：如果后面加上with check option 则被授权的用户可以再去给其他的用户授权

不能查看全部信息，只能查看被授权的

MariaDB [hellodb]> select * from students;
ERROR 1142 (42000): SELECT command denied to user ‘root‘@‘192.168.40.134‘ for table ‘students‘
MariaDB [hellodb]> select name,gender from students;
+----------------+--------+
| name | gender |

查看指定用户获得的授权：

Help SHOW GRANTS SHOW GRANTS FOR ‘user‘@‘host‘;

MariaDB [(none)]> show grants for [email protected]‘192.168.40.134;

注意：MariaDB服务进程启动时会读取mysql库中所有授权表至内存

(1)GRANT或REVOKE等执行权限操作会保存于系统表中，MariaDB的服务进程通常会自动重读授权表，使之生效

(2) 对于不能够或不能及时重读授权表的命令，可手动让MariaDB的服务进程重读授权表：mysql> FLUSH PRIVILEGES;

回收授权
revoke select,insert on hellodb.view_student from [email protected]‘192.168.40.134;

授权和创建用户一起

grant select (stuid,name) on students to [email protected]’192.168.40.14 7identified by ‘centos’;

所有被授权的信息都存在mysql库中的columns_priv，等以.priv结尾的数据库中

存储引擎

?MyISAM引擎文件：

tbl_name.frm: 表格式定义

tbl_name.MYD: 数据文件

tbl_name.MYI: 索引文件

查看mysql支持的存储引擎: show engines; ?

查看当前默认的存储引擎: show variables like ‘%storage_engine%‘; ?

设置默认的存储引擎：

vim /etc/my.conf

[mysqld]

default_storage_engine= InnoDB;

?查看库中所有表使用的存储引擎

Show table status from db_name; ?

查看库中指定表的存储引擎

show table status like ‘ tb_name ‘;

show create table tb_name; ?

设置表的存储引擎：

CREATE TABLE tb_name(... ) ENGINE=InnoDB;

ALTER TABLE tb_name ENGINE=InnoDB;

约束
查看所有约束
select * from information_schema.`table_constraints`G;

非空约束

建表时指定
create table t2(id int(10) not null,name varchar(5));

已存在的表增加约束
alter table t2 modify name varchar(5) not null;

MariaDB [hellodb]> insert into t2 values(3,null);
ERROR 1048 (23000): Column ‘name‘ cannot be null

删除非空约束 (重新定义)

alter table t2 modify name varchar(5);

查看创建表的详细信息

MariaDB [hellodb]> show create table t2;
+-------+--------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                       |
+-------+--------------------------------------------------------------------------------------------------------------------+
| t2    | CREATE TABLE `t2` (
   `id` int(10) NOT NULL,
   `name` varchar(5) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+--------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

唯一性约束
create table t3(userid int(10) unique,name varchar(10));

向表中添加信息（不能重复）

MariaDB [hellodb]> insert into t3 values(1,‘lif‘);
Query OK, 1 row affected (0.01 sec)

MariaDB [hellodb]> insert into t3 values(1,‘fhj‘);
ERROR 1062 (23000): Duplicate entry ‘1‘ for key ‘userid‘

复合唯一性约束
     create table t_user(
     -> user_id int(10),
     -> user_name varchar(30),
     -> id_card varchar(18),
     -> constraint un_userid_idcard unique(user_id,id_card)
     -> );

MariaDB [hellodb]> select * from t_user;
+---------+-----------+--------------------+
| user_id | user_name | id_card            |
+---------+-----------+--------------------+
|       1 | fh        | 123456789456123123 |
|       2 | ms        | 123456789456123123 |
|       1 | ms        | 123456789456123124 |
+---------+-----------+--------------------+
3 rows in set (0.00 sec)

注意：复合唯一性约束时，必须同时满足几个条件才能唯一约束，满足任何一个都不会受到约束

增加约束

alter table t6 modify id int unique;

查看指定表的约束信息

alter table t6 add constraint un_t6_name unique(name);

删除约束通过重定义或者通过索引删除
alter table t6 drop index un_t6_name;

主键约束
建表时添加
create table test1(user_id int(10) primary key,name varchar(10));

主键非空且唯一

MariaDB [hellodb]> insert into test1 values (null,‘ms‘);
ERROR 1048 (23000): Column ‘user_id‘ cannot be null
MariaDB [hellodb]> insert into test1 values (1,‘ms‘);
Query OK, 1 row affected (0.00 sec)

MariaDB [hellodb]> insert into test1 values (1,‘ms‘);
ERROR 1062 (23000): Duplicate entry ‘1‘ for key ‘PRIMARY‘

     删除主键
     alter table test1 drop primary key;
     表存在时增加主键
     alter table test1 modify user_id int(10) primary key;
     alter table test1 add constraint test1_user_id_pk primary key (user_id);

    复合主键
     create table test2 (
     -> user_id int(10),
     -> user_name varchar(30),
     -> age tinyint unsigned,
     -> constraint test2_userid_username_pk primary key (user_id,user_name)
     -> );

注意：在一张表上不能创建多个主键,但是主键可以由两列一起组成

外键（myisam不支持外键）

详细查看一个表的信息

MariaDB [ms]> select * from information_schema.table_constraints where table_name=‘students‘ and constraint_schema=‘ms‘;

展示创建表的信息

MariaDB [ms]> show create table students;
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                                                                                                                                                                   |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| students | CREATE TABLE `students` (
   `id` int(10) unsigned NOT NULL,
   `name` varchar(10) DEFAULT NULL,
   `age` tinyint(3) unsigned DEFAULT NULL,
   `classid` tinyint(3) unsigned DEFAULT NULL,
   PRIMARY KEY (`id`),
   KEY `ms_stu_class_fk` (`classid`),
   CONSTRAINT `ms_stu_class_fk` FOREIGN KEY (`classid`) REFERENCES `classes` (`class`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

给现有表增加外键
alter table students add constraint mage_stu_class_fk foreign key(classid) references classes(classid);

增加外键之后，再往含有外键的表中添加没有班级号的学生，会报错，只能添加有班级的学生。

MariaDB [ms]> insert into students values (3,‘rgh‘,46,5);
ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`ms`.`students`, CONSTRAINT `ms_stu_class_fk` FOREIGN KEY (`classid`) REFERENCES `classes` (`class`))
MariaDB [ms]> insert into students values (3,‘rgh‘,46,3);
Query OK, 1 row affected (0.00 sec)

当一个表是另一个表的外键时，不能直接删除其内容，要想能删除，需要级联

MariaDB [ms]> delete from classes where class=3;
ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`ms`.`students`, CONSTRAINT `ms_stu_class_fk` FOREIGN KEY (`classid`) REFERENCES `classes` (`class`))

级联删除（删除不含外键表里的内容时，含有外键的表也跟着删除）

alter table students add constraint mage_stu_class_fk foreign key (classid) references classes (classid) on delete cascade;

MariaDB [ms]> delete from classes where class=3;
Query OK, 1 row affected (0.00 sec)

MariaDB [ms]> select * from students;select * from classes;;
+----+------+------+---------+
| id | name | age | classid |
+----+------+------+---------+
| 1 | fk | 40 | 1 |
| 2 | ms | 29 | 2 |
+----+------+------+---------+
2 rows in set (0.00 sec)

+-------+-----------+
| class | classname |
+-------+-----------+
| 1 | xigong |
| 2 | donggong |
+-------+-----------+
2 rows in set (0.00 sec)

不会被级联删除，但是会设置为null

alter table students add constraint mage_stu_class_fk foreign key (classid) references classes (classid) on delete set null;

更新不含外键表里的内容时，含有外键的表也跟着更新

alter table students add constraint mage_stu_class_fk foreign key (classid) references classes (classid) on update cascade;

    自增长
     增加
     alter table students modify id int(10) unsigned auto_increment;
     删除
     alter table students modify id int(10) unsigned ;

检查约束
在mysql中不支持.

系统变量
set sql_mode=‘tranditional‘;

     使用索引
     查看指定表上的所有索引
     show indexes from studentsG;

创建索引
create index index_age on students(age);

查看是否使用索引
explain select * from students where age=20G

统计索引使用的次数
set global userstat=1;

exit重连

show index_statistics;

以上是关于mysql之视图存储过程触发器约束授权的主要内容，如果未能解决你的问题，请参考以下文章

mysql之视图触发器事务存储过程函数

MySQL进阶篇之视图/存储过程/触发器

春华秋实之MySQL进阶-04 视图/存储过程/触发器

MySQL之视图触发器事务存储过程函数

MySQL 视图触发器函数存储过程

python-day48--mysql之视图触发器事务存储过程函数