-- Sequence 管理表DROP TABLE IF EXISTS sequence;CREATE TABLE sequence (         name VARCHAR(50) NOT NULL,         current_value INT NOT NULL,         increment INT NOT NULL DEFAULT 1,         PRIMARY KEY (name)) ENGINE=InnoDB; -- 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 ; -- 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 ; -- 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 ;/*-- 测试INSERT INTO sequence VALUES ('TestSeq', 0, 1);SELECT SETVAL('TestSeq', 10);SELECT CURRVAL('TestSeq');SELECT NEXTVAL('TestSeq');*/