添加图书,并触发触发器trg_Book_ins修改在册数量

在library数据库
创建该触发器后
create trigger Trg_Book_ins after insert on Book for each row
update Book set B_RegisteredNumber=(select count(*) from Book,inserted where Book.B_ISBN=inserted.B_ISBN and Book.B_State=1);
向Book表插入数据时,提示Table 'library.Inserted' doesn't exist

这个问题可能是因为"inserted"表不存在。在触发器中,"inserted"是一个特殊的虚拟表,用于访问执行触发操作时新插入的行。

您可以修改该触发器如下:

CREATE TRIGGER Trg_Book_ins
AFTER INSERT ON Book
FOR EACH ROW
BEGIN
  UPDATE Book
  SET B_RegisteredNumber=(SELECT COUNT(*) FROM Book WHERE B_ISBN=NEW.B_ISBN AND B_State=1);
END;