* 建库、建表、添加数据

CREATE DATABASE chapter06;

USE chapter06;

CREATE TABLE account(

id INT primary key auto_increment,

name VARCHAR(40),

money FLOAT

);

INSERT INTO account(name,money) VALUES('a',1000);

INSERT INTO account (name, money) VALUES ('b', 1000);

#### 【例6-1】

START TRANSACTION;

UPDATE account SET money=money-100 WHERE NAME='a';

UPDATE account SET money=money+100 WHERE NAME='b';

COMMIT;

* 查询

SELECT * FROM account;

-----------------------------------------------------------------------------------------------

##### 6.1.2事务的提交

* 使用UPDATE语句实现由b账户向a账户转100元钱的转账功能，

START TRANSACTION;

UPDATE account SET money=money+100 WHERE name='a';

UPDATE account SET money=money-100 WHERE name='b';

* 查询

SELECT * FROM account;

* 使用commit语句来提交事务

START TRANSACTION;

UPDATE account SET money=money+100 WHERE name='a';

UPDATE account SET money=money-100 WHERE name='b';

COMMIT;

------------------------------------------------------------------------------------------------

##### 6.1.3事务的回滚

* 使用UPDATE语句实现由b账户向a账户转100元钱的转账功能，

START TRANSACTION;

UPDATE account SET money=money+100 WHERE name='a';

UPDATE account SET money=money-100 WHERE name='b';

* 事务回滚

ROLLBACK;

------------------------------------------------------------------------------------------------

##### 6.1.4事务的隔离级别

(1)设置B账户中事务的隔离级别

SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;

#查询事务隔离级别

SELECT @@tx_isolation;

(2)演示脏读

START TRANSACTION;

UPDATE account SET money=money-100 WHERE name='a';

UPDATE account SET money=money+100 WHERE name='b';

* 查询

SELECT * FROM account;

(3)设置b账户中事务的隔离级别

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;

(4)验证是否出现脏读

START TRANSACTION;

START TRANSACTION;

UPDATE account SET money=money-100 WHERE name='a';

UPDATE account SET money=money+100 WHERE name='b';

* 查询

SELECT * FROM account;

------------------------------------------------------------------------------------------------

##### 6.2存储过程的创建

* 建表

USE chapter06;

CREATE TABLE student(

id INT(3) PRIMARY KEY AUTO_INCREMENT,

name VARCHAR(20) NOT NULL,

grade FLOAT,

gender CHAR(2)

);

* 添加数据

INSERT INTO student(name,grade,gender)

VALUES('tom',60,'男'),

('jack',70,'男'),

('rose',90,'女'),

('lucy',100,'女');

#### 【例6-2】

CREATE PROCEDURE Proc()

BEGIN

SELECT * FROM student;

END;

#### 【例6-3】

DECLARE s_grade FLOAT;

DECLARE s_gender CHAR(2);

SELECT grade, gender INTO s_grade, s_gender

FROM student WHERE name = 'rose';

#### 【例6-4】

//方法一：使用sqlstate_value

DECLARE command_not_allowed CONDITION FOR SQLSTATE'42000';

//方法二：使用mysql_error_code

DECLARE command_not_allowed CONDITION FOR 1148;

#### 【例6-5】

//方法一：捕获sqlstate_value

DECLARE CONTINUE HANDLER FOR SQLSTATE '42S02'SET @info='NO_SUCH_TABLE';

//方法二：捕获mysql_error_code

DECLARE CONTINUE HANDLER FOR 1146 SET @info='NO_SUCH_TABLE';

//方法三：先定义条件，然后调用

DECLARE no_such_table CONDITION FOR 1146;

DECLARE CONTINUE HANDLER FOR NO_SUCH_TABLE SET @info='ERROR';

//方法四：使用SQLWARNING

DECLARE EXIT HANDLER FOR SQLWARNING SET @info='ERROR';

//方法五：使用NOT FOUND

DECLARE EXIT HANDLER FOR NOT FOUND SET @info='NO_SUCH_TABLE';

//方法六：使用SQLEXCEPTION

DECLARE EXIT HANDLER FOR SQLEXCEPTION SET @info='ERROR';

#### 【例6-6】

mysql> CREATE TABLE test.t(s1 int,primary key(s1));

Query OK, 0 rows affected (0.44 sec)

mysql> DELIMITER //

mysql> CREATE PROCEDURE demo()

-> BEGIN

-> DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' SET @x2=1;

-> SET @x=1;

-> INSERT INTO test.t VALUES(1);

-> SET @x=2;

-> INSERT INTO test.t VALUES(1);

-> SET @x=3;

-> END; //

Query OK, 0 rows affected (0.09 sec)

mysql> DELIMITER ;

mysql> CALL demo();

Query OK, 0 rows affected (0.08 sec)

mysql> SELECT @x ;

+------+

| @x |

+------+

| 3 |

+------+

1 row in set (0.00 sec)

#### 【例6-7】

CASE val

WHEN 1 THEN SELECT 'val is 1';

WHEN 2 THEN SELECT 'val is 2';

ELSE SELECT 'val is not 1or 2';

END CASE;

#### 【例6-8】

DECLARE id INT DEFAULT 0;

add_loop:LOOP

SET id=id+1;

IF id>=10 THEN LEAVE add_loop;

END IF;

END LOOP add_loop;

#### 【例6-9】

CREATE PROCEDURE doiterate()

BEGIN

DECLARE p1 INT DEFAULT 0;

my_loop:LOOP

SET p1=p1+1;

IF p1<10 THEN ITERATE my_loop;

ELSEIF p1>20 THEN LEAVE my_loop;

END IF;

SELECT 'p1 is between 10 and 20';

END LOOP my_loop;

END

#### 【例6-10】

DECLARE id INT DEFAULT 0;

REPEAT

SET id=id+1;

UNTIL id>=10;

END REPEAT;

#### 【例6-11】

DECLARE i INT DEFAULT 0;

WHILE i <10 DO

SET i=i+1;

END WHILE;

#### 【例6-12】

1、定义存储过程：

DELIMITER //

CREATE PROCEDURE CountProc1(IN s_gender VARCHAR(50),OUT num INT)

BEGIN

SELECT COUNT(*) INTO num FROM student WHERE gender = s_gender;

END //

DELIMITER ;

2、调用存储过程：

CALL CountProc1("女",@num);

3、查看返回结果：

SELECT @num;

#### 【例6-13】

SHOW PROCEDURE STATUS LIKE'C%'\G

#### 【例6-14】

SHOW CREATE PROCEDURE chapter06.CountProc1\G

#### 【例6-15】

ALTER PROCEDURE CountProc1

MODIFIES SQL DATA

SQL SECURITY INVOKER;

* 从information_schema.Routines表中查看存储过程的信息

SELECT * FROM information_schema.Routines

WHERE ROUTINE_NAME='CountProc1' AND ROUTINE_TYPE='PROCEDURE

#### 【例6-16】

DROP PROCEDURE CountProc1;

------------------------------------------------------------------------------------------------

6.4综合案例—存储过程应用

* 建表

CREATE TABLE stu(id INT,name VARCHAR(50),class VARCHAR(50));

INSERT INTO stu VALUE (1,'Lucy','class1'),(2,'Tom','class1'),(3,'Rose','class2');

* 创建存储过程

CREATE PROCEDURE addcount(out count INT)

BEGIN

DECLARE itmp INT;

DECLARE cur_id CURSOR FOR SELECT id FROM stu;

DECLARE EXIT HANDLER FOR NOT FOUND CLOSE cur_id;

SELECT count(*) INTO count FROM stu;

SET @sum=0;

OPEN cur_id;

REPEAT

FETCH cur_id INTO itmp;

IF itmp<10

THEN SET @sum= @sum+itmp;

END IF;

UNTIL 0 END REPEAT;

CLOSE cur_id;

END ;