In earlier article you have learned SQL Table
, now you learn SQL View
A VIEW is a logical set of data, can be from one table or multiple tables. Views do not contain data of their own.
View is designed for restricting direct access to the database, and exposing data as per user role.
You can say View is a just a Select statement saved in database in form of an object for better re-usability.
Why do we need View?
View is very useful when you don’t want to give access of all data of any table to particular user group, or you want to give access to some set of data without giving access of all tables.
We can create view from one table or joining multiple tables, here is an example
Create view [vwEmpSocialNetwork]
SELECT tbEmpSocialNetwork.EmpSocialId, tbEmpSocialNetwork.Facebook, tbEmpSocialNetwork.LinkedIn, tbEmpSocialNetwork.Twitter,
tbEmpSocialNetwork.PersonalBlog, tbEmpSocialNetwork.Updated, tbEmployee.FirstName, tbEmployee.MiddleName,
FROM tbEmployee left outer JOIN tbEmpSocialNetwork
ON tbEmployee.EmployeeId = tbEmpSocialNetwork.EmployeeId
Alter view viewName
Alter view [vwEmpSocialNetwork]
// Specify all column names you want in view
drop view viewName
drop view [vwEmpSocialNetwork]
Here you can see how to check dependency of any view, Just right click on view and then select "View Dependency"
You also can set permission of any view to particular user or user role,
Right Click => Select Properties