1. Create a view
The view is established for the efficiency of the query. The view is only a part of the data of the table, and the query speed will be faster than directly querying a table.
The view can only display the data you need, and the unneeded data can not disappear, so the idea of directly operating the view query is clearer than directly operating the basic table.
Create a view of the School of Information students
create view is_student
as
select Sno, Sname, Sage
from student
where Sdept='Information Institute'
with check option;
2. Create an index
Establishing a unique index in ascending order of student numbers also improves the query rate.
create unique index Stusno on student(Snow);