mysql使用触发器或函数实现自增序列

MySQL This function has none of DETERMINISTIC, NO SQL...错误1418 的原因分析及解决方法

http://blog.csdn.net/ty_soft/article/details/6940190

一、单独的数据表+函数：

如果你不想使用mysql的自动递增，但又想实现主键序列号的功能，可以使用下面的方法，通过函数用一张表去维护生成多个表的序列号，简单又实用

1.创建生成多个表的序列号的数据维护表

CREATE TABLE seq (
name varchar(20) NOT NULL,
val int(10) UNSIGNED NOT NULL,
PRIMARY KEY (name)
) ENGINE=InnoDB DEFAULT CHARSET=UTF8;

2.插入几条初始化数据

INSERT INTO seq VALUES('one',100);
INSERT INTO seq VALUES('two',1000);

3.创建函数以生成序列号

CREATE FUNCTION seq(seq_name char (20)) returns int
begin
UPDATE seq SET val=last_insert_id(val+1) WHERE name=seq_name;
RETURN last_insert_id();
end

4.测试

mysql> SELECT seq ( 'one' ),seq ( 'two' ),seq ( 'one' ),seq ( 'one' );
+ ------------+------------+------------+------------+
| seq ( 'one' ) | seq ( 'two' ) | seq ( 'one' ) | seq ( 'one' ) |
+ ------------+------------+------------+------------+
| 102 | 1002 | 103 | 104 |
+ ------------+------------+------------+------------+
1 row IN SET ( 0. 00 sec )

二、触发器

原理是在建立一个触发器TRIGGER tri_NewBH 在table插入时执行序列计算

mysql> CREATE TABLE tb(BH CHAR(16),content VARCHAR(20),`date` DATETIME,val INT);
Query OK, 0 rows affected (0.05 sec)

mysql>
mysql>
mysql> DELIMITER $$
mysql> DROP TRIGGER IF EXISTS tri_NewBH $$
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>
mysql> CREATE TRIGGER tri_NewBH BEFORE INSERT ON tb
    -> FOR EACH ROW
    -> BEGIN
    ->     DECLARE dt CHAR(8);
    ->     DECLARE bh_id CHAR(16);
    ->     DECLARE number INT;
    ->     DECLARE new_bh VARCHAR(16);
    ->
    ->     SET dt = DATE_FORMAT(CURDATE(),'%Y%m%d');
    ->
    ->     SELECT
    ->         MAX(BH) INTO bh_id
    ->     FROM tb
    ->     WHERE BH LIKE CONCAT(dt,'%');
    ->
    ->     IF bh_id = '' OR bh_id IS NULL THEN
    ->         SET new_bh = CONCAT(dt,'00000001');
    ->     ELSE
    ->         SET number = RIGHT(bh_id,8) + 1;
    ->         SET new_bh =  RIGHT(CONCAT('00000000',number),8);
    ->         SET new_bh=CONCAT(dt,new_bh);
    ->     END IF;
    ->
    ->     SET NEW.BH = new_bh;
    -> END$$
Query OK, 0 rows affected (0.09 sec)

mysql>
mysql> DELIMITER ;
mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO tb(content,`date`,val) VALUES('LiangCK','2009-05-11',20);
Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM tb;
+------------------+---------+---------------------+------+
| BH               | content | date                | val  |
+------------------+---------+---------------------+------+
| 2009051100000001 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2009051100000002 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2009051100000003 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2009051100000004 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2011051200000001 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2011051200000002 | LiangCK | 2009-05-11 00:00:00 |   20 |
| 2011051200000003 | LiangCK | 2009-05-11 00:00:00 |   20 |
+------------------+---------+---------------------+------+
7 rows in set (0.00 sec)

三、下面就是另外一个的实现方案:

原理是创建一个专门记录序列的表sequence,记录有当前序列号,序列的间隔如+1

Sql代码

DROP TABLE IF EXISTS sequence;/*创建记录当前序列的表*/
CREATE TABLE sequence (
name VARCHAR(50) NOT NULL,
current_value INT NOT NULL,
increment INT NOT NULL DEFAULT 1,
PRIMARY KEY (name)
) ENGINE=InnoDB;
INSERT INTO sequence VALUES ('MovieSeq',3,5);
DROP FUNCTION IF EXISTS currval;
DELIMITER $/*创建一个获取当前序列的function*/
CREATE FUNCTION currval (seq_name VARCHAR(50))
RETURNS INTEGER
CONTAINS SQL
BEGIN
DECLARE value INTEGER;
SET value = 0;
SELECT current_value INTO value
FROM sequence
WHERE name = seq_name;
RETURN value;
END$
DELIMITER ;

测试一下结果：

Sql代码

mysql> SELECT currval('MovieSeq');
+---------------------+
| currval('MovieSeq') |
+---------------------+
| 3 |
+---------------------+
1 row in set (0.00 sec)
mysql> SELECT currval('x');
+--------------+
| currval('x') |
+--------------+
| 0 |
+--------------+
1 row in set, 1 warning (0.00 sec)
mysql> show warnings;
+---------+------+------------------+
| Level | Code | Message |
+---------+------+------------------+
| Warning | 1329 | No data to FETCH |
+---------+------+------------------+
1 row in set (0.00 sec)

nextval

//获取下一个数值..先在 sequence里面调用update当前最大数值+1然后再调用 currval获得当前数值

       Sql代码 
          
       
     
DROP FUNCTION IF EXISTS nextval;  
DELIMITER $  
CREATE FUNCTION nextval (seq_name VARCHAR(50))  
RETURNS INTEGER  
CONTAINS SQL  
BEGIN  
   UPDATE sequence  
   SET          current_value = current_value + increment  
   WHERE name = seq_name;  
   RETURN currval(seq_name);  
END$  
DELIMITER ;  

mysql> select nextval('MovieSeq');

      Sql代码 
         
      
    
+---------------------+  
| nextval('MovieSeq') |  
+---------------------+  
|                  15 |  
+---------------------+  
1 row in set (0.09 sec)  
  
mysql> select nextval('MovieSeq');  
+---------------------+  
| nextval('MovieSeq') |  
+---------------------+  
|                  20 |  
+---------------------+  
1 row in set (0.01 sec)  
  
mysql> select nextval('MovieSeq');  
+---------------------+  
| nextval('MovieSeq') |  
+---------------------+  
|                  25 |  
+---------------------+  
1 row in set (0.00 sec)  

setval

      Sql代码 
         
      
    
DROP FUNCTION IF EXISTS setval;  
DELIMITER $  
CREATE FUNCTION setval (seq_name VARCHAR(50), value INTEGER)  
RETURNS INTEGER  
CONTAINS SQL  
BEGIN  
   UPDATE sequence  
   SET          current_value = value  
   WHERE name = seq_name;  
   RETURN currval(seq_name);  
END$  
DELIMITER ;  

mysql> select setval('MovieSeq',150);

     Sql代码 
        
     
   
+------------------------+  
| setval('MovieSeq',150) |  
+------------------------+  
|                    150 |  
+------------------------+  
1 row in set (0.06 sec)  
  
mysql> select curval('MovieSeq');  
+---------------------+  
| currval('MovieSeq') |  
+---------------------+  
|                 150 |  
+---------------------+  
1 row in set (0.00 sec)  
  
mysql> select nextval('MovieSeq');  
+---------------------+  
| nextval('MovieSeq') |  
+---------------------+  
|                 155 |  
+---------------------+  
1 row in set (0.00 sec)  

mysql使用触发器或函数实现自增序列

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