我有以下两个数据库表：dept（dnumber，dname，founded，mgr\u ssn，budget）employee（ssn，ename，bdate，dno，salary）
我想创建一个触发器，以确保每个部门的员工都不超过8人。这是我到目前为止写的

DELIMITER //
CREATE TRIGGER ensure_dept_count_on_insert BEFORE insert on `EMPLOYEE`
    FOR EACH ROW
    BEGIN
        DECLARE maxCount integer;
        set maxCount = (select count(*) as c from Employee where Dno = new.Dno);
        if maxCount = 9
        then SIGNAL SQLSTATE '02000' SET MESSAGE_TEXT = 'Department cannot have more than 8 employees';
        end if;
    END //
DELIMITER ;

问题是，当我插入employee时，它会给我table not found异常，当删除触发器时，插入成功。