User:Vandana Sharma India/sandbox

SQL VIEWS A view can be thought of as either a virtual table or a stored query. The data accessible through a view is not stored in the database as a distinct object. What is stored in the database is a SELECT statement. The result set of the SELECT statement forms the virtual table returned by the view. A user can use this virtual table by referencing the view name in Transact-SQL statements the same way a table is referenced. A view is used to do any or all of these functions:

Restrict a user to specific rows in a table.

For example, allow an employee to see only the rows recording his or her work in a labor-tracking table. Restrict a user to specific columns.

For example, allow employees who do not work in payroll to see the name, office, work phone, and department columns in an employee table, but do not allow them to see any columns with salary information or personal information. Join columns from multiple tables so that they look like a single table.

Aggregate information instead of supplying details.

For example, present the sum of a column, or the maximum or minimum value from a column.

Views are created by defining the SELECT statement that retrieves the data to be presented by the view. The data tables referenced by the SELECT statement are known as the base tables for the view. In this example, titleview in the pubs database is a view that selects data from three base tables to present a virtual table of commonly needed data: SQL View are automatically updated when any DML statement is executed on the tables on which these are generated.