1.创建sequence表CREATE TABLE `sequence` ( `name` varchar(50) COLLATE utf8_bin NOT NULL COMMENT '序列的名字', `current_value` int(11) NOT NULL COMMENT '序列的当前值', `increment` int(11) NOT NULL DEFAULT '1' COMMENT '序列的自增值', PRIMARY KEY (`name`)) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
2.创建–取当前值的函数DROP FUNCTION IF EXISTS currval; DELIMITER $ CREATE FUNCTION currval (seq_name VARCHAR(50)) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT ''BEGIN DECLARE value INTEGER; SET value = 0; SELECT current_value INTO value FROM sequence WHERE name = seq_name; RETURN value; END$ DELIMITER ;
3.创建–取下一个值的函数DROP FUNCTION IF EXISTS nextval; DELIMITER $ CREATE FUNCTION nextval (seq_name VARCHAR(50)) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT '' BEGIN UPDATE sequence SET current_value = current_value + increment WHERE name = seq_name; RETURN currval(seq_name); END $ DELIMITER ;
4.创建–更新当前值的函数DROP FUNCTION IF EXISTS setval; DELIMITER $ CREATE FUNCTION setval (seq_name VARCHAR(50), value INTEGER) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT '' BEGIN UPDATE sequence SET current_value = value WHERE name = seq_name; RETURN currval(seq_name); END $ DELIMITER ;
5.测试添加实例 执行sqlINSERT INTO sequence VALUES ('testSeq', 0, 1);-- 添加一个sequence名称和初始值,以及自增幅度SELECT SETVAL('testSeq', 10);-- 设置指定sequence的初始值SELECT CURRVAL('testSeq');-- 查询指定sequence的当前值SELECT NEXTVAL('testSeq');-- 查询指定sequence的下一个值
DROP FUNCTION IF EXISTS currval; DELIMITER $ CREATE FUNCTION currval (seq_name VARCHAR(50)) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT ''BEGIN DECLARE value INTEGER; SET value = 0; SELECT current_value INTO value FROM sequence WHERE name = seq_name; RETURN value; END$ DELIMITER ;
3.创建–取下一个值的函数DROP FUNCTION IF EXISTS nextval; DELIMITER $ CREATE FUNCTION nextval (seq_name VARCHAR(50)) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT '' BEGIN UPDATE sequence SET current_value = current_value + increment WHERE name = seq_name; RETURN currval(seq_name); END $ DELIMITER ;
4.创建–更新当前值的函数DROP FUNCTION IF EXISTS setval; DELIMITER $ CREATE FUNCTION setval (seq_name VARCHAR(50), value INTEGER) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT '' BEGIN UPDATE sequence SET current_value = value WHERE name = seq_name; RETURN currval(seq_name); END $ DELIMITER ;
5.测试添加实例 执行sqlINSERT INTO sequence VALUES ('testSeq', 0, 1);-- 添加一个sequence名称和初始值,以及自增幅度SELECT SETVAL('testSeq', 10);-- 设置指定sequence的初始值SELECT CURRVAL('testSeq');-- 查询指定sequence的当前值SELECT NEXTVAL('testSeq');-- 查询指定sequence的下一个值
DROP FUNCTION IF EXISTS setval; DELIMITER $ CREATE FUNCTION setval (seq_name VARCHAR(50), value INTEGER) RETURNS INTEGER LANGUAGE SQL DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER COMMENT '' BEGIN UPDATE sequence SET current_value = value WHERE name = seq_name; RETURN currval(seq_name); END $ DELIMITER ;
5.测试添加实例 执行sqlINSERT INTO sequence VALUES ('testSeq', 0, 1);-- 添加一个sequence名称和初始值,以及自增幅度SELECT SETVAL('testSeq', 10);-- 设置指定sequence的初始值SELECT CURRVAL('testSeq');-- 查询指定sequence的当前值SELECT NEXTVAL('testSeq');-- 查询指定sequence的下一个值
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