MySQL自定义序列数的实现方式

DROP TABLE
  IF EXISTS sequence;
CREATE TABLE
  sequence
  (
    name VARCHAR(50) NOT NULL,
    current_value BIGINT NOT NULL,
    increment INT NOT NULL DEFAULT 1,
    PRIMARY KEY (name)
  )
  ENGINE=InnoDB;

INSERT INTO sequence VALUES ('seq1', 0, 1);
INSERT INTO sequence VALUES ('seq2', 0, 1);
...

DROP FUNCTioN IF EXISTS `seq`; 
DELIMITER $$ 
CREATE FUNCTION `seq`(seq_name char (20)) returns BIGINT
BEGIN
 UPDATE sequence SET current_value=last_insert_id(current_value + increment) WHERE name=seq_name;
 RETURN last_insert_id();
END $$
DELIMITER ;

<select id="getRowkeyByName" parameterType="java.lang.String" resultType="long">
  select `seq`(
    #{name}
  )
</select>

use aglog;
 
-- 创建公共的序列表
DROP TABLE IF EXISTS t_common_sequence;
CREATE TABLE t_common_sequence (
  seq_name VARCHAR(100) NOT NULL COMMENT '序列名称',
  current_val INT NOT NULL COMMENT '当前值',
  increment_val INT NOT NULL DEFAULT '1' COMMENT '增长值 默认1',
  PRIMARY KEY(seq_name)
)
ENGINE = InnoDB
CHARACTER SET = utf8
COMMENT='公共的序列表';
 
-- 创建函数，获取指定名称的 当前序列值
DELIMITER //
DROP FUNCTION IF EXISTS f_currval;
CREATE FUNCTION f_currval(v_seq_name VARCHAR(100))
RETURNS INT
BEGIN
  DECLARE value INT;
  SET value = 0;
  SELECT current_val into value 
  FROM t_common_sequence
  WHERE seq_name = v_seq_name;
  RETURN value;
END;
//
DELIMITER ;
 
-- 创建函数，获取指定名称的 下一个序列值
DELIMITER //
DROP FUNCTION IF EXISTS f_nextval;
CREATE FUNCTION f_nextval(v_seq_name VARCHAR(100))
RETURNS INT
BEGIN
  UPDATE t_common_sequence
  SET current_val = current_val + increment_val
  WHERE seq_name = v_seq_name;
  RETURN f_currval(v_seq_name);
END;
//
DELIMITER ;
 
-- 创建函数，修改指定名称的序列值，并返回
DELIMITER //
DROP FUNCTION IF EXISTS f_setval;
CREATE FUNCTION f_setval(v_seq_name VARCHAR(100), v_new_val INT)
RETURNS INT
BEGIN
  UPDATE t_common_sequence
  SET current_val = v_new_val
  WHERE seq_name = v_seq_name;
  RETURN f_currval(v_seq_name);
END;
//
DELIMITER ;

insert into t_common_sequence(seq_name,current_val,increment_val) values('seq_job',1,1);
commit;
 
 
-- 获取当前序列
select f_currval('seq_job');
 
-- 获取下一个序列
select f_nextval('seq_job');
 
-- 设置序列值，并返回
select f_setval('seq_job',10);
 
select * from t_common_sequence;