This tutorial gives an overview of views that can be created on tables and demonstrates the same. Some of the benefits of views are discussed.
Business data contains multiple tables and queries typically address only some relevant data in the tables. A full table scan during query processing in such cases may be avoided.
Business data invariably contains sensitive information. A view can restrict access to this sensitive information from user to user thus ensuring security of data.
Views are created over the tables for faster query processing and protecting sensitive information present in some tables
A view is an efficient way of representing data without the need to maintain it. A view is not an actual table and requires no permanent storage. A "virtual table" is created and used. It consists of a stored query accessible as a virtual table composed of the result set of a query. Unlike ordinary tables (base tables) in a relational database, a view does not form part of the physical schema: it is a dynamic, virtual table computed or collated from data in the database. Changing the data in a table alters the data shown in subsequent invocations of the view.
Views can provide advantages over tables :