What Is A View?

In the context of relational database design a view is how a user "sees" or uses the information contained in a database. Usually, a single view represents a particular business function and there may be many different views of the same data.

For example, a form submission page on a web site usually represents a single view of an underlying database (although views are certainly not limited to web pages or browser interfaces).

A single view may represent data (attributes) from multiple tables and may allow or deny operations available through other views.

For a general example, a non-priviledged user may see their records through a view which allows them to review and possibly change personal information such as email address or telephone number - but certainly not their access priviledges or bank balance! But an administrative user may have a view that allows access to all the user's attributes, including the ability to create, change or delete the records. These represent two different views of the database.

Views provide much more value than simply the user interface, they are also a powerful tool for maintaining a database over time! During the lifetime of your data it is very probable that the physical storage and table definitions will change from time to time. When this happens, every user or user interface must be advised of the changes and must "learn" to adapt to the changes. However, the views provide an abstraction layer that may be easily reconfigured to find data in new places, under new names, while presenting an unchanged interface to the users. In other words, views allow you to maintain and change your database without inconvenience to users of the data!

Some database products support views, others do not. Some that do support views do not support all operations across multiple tables.

Our View Base Class supports unlimited views and all operations across multiple tables - even on RDBMSs that do not natively support views!