views, triggers

Views: can only be queried for use, cannot add data and modify data
Consider a query result as a virtual table
Select *from (Xunibiao) as xunibiaoming where condition
Modify a View
Alter VIEW SHITU1
As
Select *from Studento
Delete a view
Drop View SHITU1
Trigger
---triggers---special stored procedures. automatically triggered by adding or removing changes to the database table
Create Trigger Tr_student_insert
On student--which table to build the trigger on
For Insert--for is added after the trigger, for can also be written after--after what what to trigger
As
Begin
Select *from Student
End
Go
INSERT into student values ()--parentheses are all columns in the file

Create Trigger Tr_student_delete
On student
Instead of delete
As
Begin
DECLARE @sno int
Select @sno =sno from deleted
Delete from
End
Go
Delete from student
Select *from Student
Create Trigger Tr_student_delete
On student
Instead of delete
As
Begin
Select *from deleted--deleted is a temporary table to get the data
End
Go

views, triggers