sql从开始删除

Question

是否有无论如何我可以限制在一个表中允许的行数量说40，然后当41st添加时，该表删除第一个？

Answer 1

CREATE TABLE animals (
id MEDIUMINT NOT NULL AUTO_INCREMENT, 
name CHAR(30) NOT NULL, 
PRIMARY KEY (id) 
); 

-- if this is 41st record, ... 
-- the statement below will delete the id with 1, and so forth 
insert into animals(name) values('wolverine'); 
delete from animals where id <= LAST_INSERT_ID() - 40; 

Answer 2

是的，你可以用触发器做到这一点。您使用的是什么RDMS？