写一个触发器

create table DiaryType
(
Dtid int identity(1,1) primary key not null, --日记类型主键
Dtype varchar(10) not null, --日记类型
)

create table Diary
(
Did int identity(1,1) primary key not null, --日记主键
Uid int not null foreign key references Users(Uid), --发表用户ID
Dtid int not null foreign key references DiaryType(Dtid), --日记类型ID
Dtitle varchar(50) not null, --日记标题
Dcontent varchar(5000) not null, --内容
Dtime datetime not null, --发表时间
)

create table Critique
(
Cid int identity(1,1) primary key not null, --评论主键
Did int not null foreign key references Diary(Did), --日记ID
Uid int not null foreign key references Users(Uid), --评论用户ID
Ccontent varchar(5000) not null, --评论内容
Ctime datetime not null, --评论时间
)

怎么样写一个删除日记，而且会直接删除日记下的评论的触发器（使用删除时，暂时使约束无效的触发器）

create trigger trg_drop on Diary instead of delete

as
declare cur_did cursor
for select Did from deleted
open cur_did
declare @did int
fetch next from cur_did into @did
while @@fetch_status=0
begin
delete from Critique where did=@did

delete from Diary where did=@did
fetch next from cur_dd into @did
end
close cur_did
deallocate cur_did
go

Create or replace trigger trigger_delete before delete on DiaryType for each row begin delete from Critique where Did=:old.Did end;