A view is a virtual table whose contents are defined by a query. Like a table, a view consists of a set of named columns and rows of data. Unless indexed, a view does not exist as a stored set of data values in a database. The rows and columns of data come from tables referenced in the query defining the view and are produced dynamically when the view is referenced.

A view acts as a filter on the underlying tables referenced in the view. The query that defines the view can be from one or more tables or from other views in the current or other databases. Distributed queries can also be used to define views that use data from multiple heterogeneous sources. This is useful, for example, if you want to combine similarly structured data from different servers, each of which stores data for a different region of your organization.

Views are generally used to focus, simplify, and customize the perception each user has of the database. Views can be used as security mechanisms by letting users access data through the view, without granting the users permissions to directly access the underlying base tables of the view. Views can be used to provide a backward compatible interface to emulate a table that used to exist but whose schema has changed. Views can also be used when you copy data to and from SQL Server to improve performance and to partition data.

Types Of View in SQL Server

Besides the standard role of basic user-defined views, SQL Server provides the following types of views that serve special purposes in a database.

Create View in SQL Server

                                CREATE VIEW DB_DNP.EmployeeHireDate  
                                AS  
                                SELECT p.FirstName, p.LastName, e.HireDate  
                                FROM HumanResources.Employee AS e JOIN Person.Person AS  p  
                                ON e.BusinessEntityID = p.BusinessEntityID ;   
                                GO  
                                -- Query the view  
                                SELECT FirstName, LastName, HireDate  
                                FROM DB_DNP.EmployeeHireDate  
                                ORDER BY LastName;