ASA SQL User's Guide
  Working with Database Objects

Working with views

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 UPDATE, 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.

• You cannot perform UPDATE, INSERT, and DELETE operations on all 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 access 

Views let you tailor access to data in the database. Tailoring access serves several purposes:

• Improved security    By allowing access to only the information that is relevant.

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

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

Creating views
Using views
Using the WITH CHECK OPTION clause
Modifying views
Deleting views
Browsing the information in views
Views in the system tables