Views enable you to save frequently used or complex queries, then access them in a SELECT statement as if they were a table. A view is not physically materialized on disk: the query runs as a subquery when you access the view.
These topics describe various aspects of creating and managing views:
- Best Practices when Creating Views outlines best practices when creating views.
- Working with View Dependencies contains examples of listing view information and determining what views depend on a certain object.
- About View Storage in Greenplum Database describes the mechanics behind view dependencies.
Creating Views
The CREATE VIEWcommand defines a view of a query. For example:
CREATE VIEW comedies AS SELECT * FROM films WHERE kind = 'comedy';
Views ignore ORDER BY and SORT operations stored in the view.
Dropping Views
The DROP VIEW command removes a view. For example:
DROP VIEW topten;
The DROP VIEW...CASCADE command also removes all dependent objects. As an example, if another view depends on the view which is about to be dropped, the other view will be dropped as well. Without the CASCADE option, the DROP VIEW command will fail.
