#建庫、建表、添加數據
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);mysql
【例6-1】
START TRANSACTION;
UPDATE account SET money=money-100 WHERE NAME='a';
UPDATE account SET money=money+100 WHERE NAME='b';
COMMIT;sql
#查詢
SELECT * FROM account;
-----------------------------------------------------------------------------------------------
6.1.2 事務的提交oop
#使用UPDATE語句實現由b帳戶向a帳戶轉100元錢的轉帳功能，
START TRANSACTION;
UPDATE account SET money=money+100 WHERE name='a';
UPDATE account SET money=money-100 WHERE name='b';code
#查詢
SELECT * FROM account;orm
#使用commit語句來提交事務
START TRANSACTION;
UPDATE account SET money=money+100 WHERE name='a';
UPDATE account SET money=money-100 WHERE name='b';
COMMIT;事務
------------------------------------------------------------------------------------------------rem
6.1.3 事務的回滾編譯器
#使用UPDATE語句實現由b帳戶向a帳戶轉100元錢的轉帳功能，
START TRANSACTION;
UPDATE account SET money=money+100 WHERE name='a';
UPDATE account SET money=money-100 WHERE name='b';it
#事務回滾
ROLLBACK;io
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6.1.4 事務的隔離級別
（1）設置B帳戶中事務的隔離級別
SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
#查詢事務隔離級別
SELECT @@tx_isolation;
（2）演示髒讀
START TRANSACTION;
UPDATE account SET money=money-100 WHERE name='a';
UPDATE account SET money=money+100 WHERE name='b';
#查詢
SELECT * FROM account;
（3）設置b帳戶中事務的隔離級別
SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
（4）驗證是否出現髒讀
START TRANSACTION;
START TRANSACTION;
UPDATE account SET money=money-100 WHERE name='a';
UPDATE account SET money=money+100 WHERE name='b';
#查詢
SELECT * FROM account;
------------------------------------------------------------------------------------------------
6.2 存儲過程的建立
#建表
USE chapter06;
CREATE TABLE student(
id INT(3) PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
grade FLOAT,
gender CHAR(2)
);
#添加數據
INSERT INTO student(name,grade,gender)
VALUES('tom',60,'男'),
('jack',70,'男'),
('rose',90,'女'),
('lucy',100,'女');
【例6-2】
DELIMITER //
CREATE PROCEDURE Proc()
BEGIN
SELECT * FROM student;
END
//
還原
DELIMITER ;
DELIMITER //和DELIMITER ;兩句，DELIMITER是分割符的意思，由於MySQL默認以";"爲分隔符，若是咱們沒有聲明分割符，
那麼編譯器會把存儲過程當成SQL語句進行處理，則存儲過程的編譯過程會報錯，
因此要事先用DELIMITER關鍵字申明當前段分隔符，
這樣MySQL纔會將";"當作存儲過程當中的代碼，不會執行這些代碼，
用完了以後要把分隔符還原。
【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：捕獲sqlstate_value
DECLARE CONTINUE HANDLER FOR SQLSTATE '42S02'SET @info='NO_SUCH_TABLE';
//方法二：捕獲mysql_error_code
DECLARE CONTINUE HANDLER FOR 1146 SET @info='NO_SUCH_TABLE';
//方法三：先定義條件，而後調用
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】
一、定義存儲過程：
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 ;
二、調用存儲過程：
CALL CountProc1("女",@num);
三、查看返回結果：
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;
#從information_schema.Routines表中查看存儲過程的信息
SELECT * FROM information_schema.Routines
WHERE ROUTINE_NAME='CountProc1' AND ROUTINE_TYPE='PROCEDURE
【例6-16】
DROP PROCEDURE CountProc1;
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6.4 綜合案例—存儲過程應用
#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');
#建立存儲過程CREATE PROCEDURE addcount(out count INT)BEGINDECLARE 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;REPEATFETCH cur_id INTO itmp;IF itmp<10THEN SET @sum= @sum+itmp;END IF;UNTIL 0 END REPEAT;CLOSE cur_id;END ;