View Management

Views are computed tables.

You can use views to show database users exactly the information you want to present, in a format you can control.

Similarities between Views and Base Tables

Views are similar to the permanent tables of the database (a permanent table is also called a base table) in many ways:

  • You can assign access permissions to views just as to base tables.

  • You can perform SELECT queries on views.

  • You can perform INSERT and DELETE operations on some views.

  • You can create views based on other views.

Differences Between Views and Permanent Tables

There are some differences between views and permanent tables:

  • You cannot create indexes on views.

  • INSERT, DELETE, and UPDATE operations can only be performed on certain views.

  • You cannot assign integrity constraints and keys to views.

  • Views refer to the information in base tables, but do not hold copies of that information. Views are recomputed each time you invoke them.

Benefits of Tailoring Data Access

Views are used to tailor access to data in the database. Tailoring access serves several purposes:

  • By not allowing access to information that is not relevant.

  • By presenting users and application developers with data in a more easily understood form than in the base tables.

  • By centralizing in the database the definition of common queries.

Related concepts
Views and Procedures Provide Extra Security