This topic describes how to create a materialized view.

Syntax

CREATE MATERIALIZED VIEW name
[build clause][create mv refresh] AS subquery

Where build_clause is:

BUILD {IMMEDIATE | DEFERRED}

Where create_mv_refresh is:

REFRESH [COMPLETE] [ON DEMAND]

Parameters

Parameter Description
name The name of a view to be created. The name can be schema-qualified.
subquery A SELECT statement that specifies the contents of the view. For more information about valid queries, see SELECT.
build clause Include a build_clause to specify when the view is populated. Specify BUILD IMMEDIATE, or BUILD DEFERRED:
  • BUILD IMMEDIATE instructs the server to populate the view immediately. This is the default behavior.
  • BUILD DEFERRED instructs the server to populate the view at a later time during a REFRESH operation.
create mv refresh Include the create mv refresh clause to specify when the contents of a materialized view must be updated. The clause contains the REFRESH keyword followed by COMPLETE and/or ON DEMAND, where:
  • COMPLETE instructs the server to discard the current content and reload the materialized view by executing the defining query of the view when the materialized view is refreshed.
  • ON DEMAND instructs the server to refresh the materialized view on demand by calling the DBMS_MVIEW package or by calling the Postgres REFRESH MATERIALIZED VIEW statement. This is the default behavior.

Description

CREATE MATERIALIZED VIEW defines a view of a query that is not updated each time the view is referenced in a query. By default, the view is populated when the view is created. You can include the BUILD DEFERRED keywords to delay the population of the view.

A materialized view can be schema-qualified. If you specify a schema name when executing the CREATE MATERIALIZED VIEW statement, the view will be created in the specified schema. The view name must be distinct from the name of any other view, table, sequence, or index in the same schema.

Note
  • Materialized views are read-only. The server will not allow an INSERT, UPDATE, or DELETE operation on a view.
  • Access to tables referenced in the view is determined by permissions of the view owner. The user of a view must have permissions to call all functions used by the view.
  • For more information about the Postgres REFRESH MATERIALIZED VIEW statement, see the PostgreSQL Core Documentation.

Examples

The following statement creates a materialized view named dept_30:

CREATE MATERIALIZED VIEW dept_30 BUILD IMMEDIATE AS SELECT * FROM emp WHERE deptno = 30;