View in Sql is useful when we want to fetch data from multiple tables with complex join, You also can set permission to view to control who can view the data.
View is the logical set of data; we can create sql view from one or multiple tables, SQL View is read-only data; learn how to create view in SQL
In earlier article you have learned SQL Table, now you learn SQL View
Why do we need View in SQL?
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] As SELECT tbEmpSocialNetwork.EmpSocialId, tbEmpSocialNetwork.Facebook, tbEmpSocialNetwork.LinkedIn, tbEmpSocialNetwork.Twitter, tbEmpSocialNetwork.PersonalBlog, tbEmpSocialNetwork.Updated, tbEmployee.FirstName, tbEmployee.MiddleName, tbEmployee.LastName, tbEmployee.EmployeeId FROM tbEmployee left outer JOIN tbEmpSocialNetwork ON tbEmployee.EmployeeId = tbEmpSocialNetwork.EmployeeId
Altering sql view means making any modification in View syntax, that will not have any impact on data, but the output may change
Alter view [vwEmpSocialNetwork] As SELECT // Specify all column names you want in view
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
As you can see in the above picture, you can set permission to sql view, give permission to user or some roles to access your view
Dropping view means deleting the view from database permanently
drop view [vwEmpSocialNetwork]
Remember once you drop the view, the object will be deleted from database, means all the sql query joins you wrote in view, will be gone permanently, so, be careful, alternately, you can rename it with version number to keep the backup.