Index for Section VIEW

Alphabetical listing for C

Bottom of page

CREATE
NAME
  CREATE VIEW - define a new view

SYNOPSIS
  CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW name [ ( column_name [, ...] ) ]
      AS query

DESCRIPTION
  CREATE VIEW defines a view of a query. The view is not physically
  materialized. Instead, the query is run every time the view is referenced
  in a query.

  CREATE OR REPLACE VIEW is similar, but if a view of the same name already
  exists, it is replaced. You can only replace a view with a new query that
  generates the identical set of columns (i.e., same column names and data
  types).

  If a schema name is given (for example, CREATE VIEW myschema.myview ...)
  then the view is created in the specified schema. Otherwise it is created
  in the current schema. Temporary views exist in a special schema, so a
  schema name may not be given when creating a temporary view. The name of
  the view must be distinct from the name of any other view, table, sequence,
  or index in the same schema.

PARAMETERS
  TEMPORARY or TEMP
       If specified, the view is created as a temporary view.  Temporary
       views are automatically dropped at the end of the current session.
       Existing permanent relations with the same name are not visible to the
       current session while the temporary view exists, unless they are
       referenced with schema-qualified names.

       If any of the tables referenced by the view are temporary, the view is
       created as a temporary view (whether TEMPORARY is specified or not).

  name The name (optionally schema-qualified) of a view to be created.

  column_name
       An optional list of names to be used for columns of the view.  If not
       given, the column names are deduced from the query.

  query
       A SELECT [select(5)] or VALUES [values(5)] command which will provide
       the columns and rows of the view.

NOTES
  Currently, views are read only: the system will not allow an insert,
  update, or delete on a view. You can get the effect of an updatable view by
  creating rules that rewrite inserts, etc. on the view into appropriate
  actions on other tables. For more information see CREATE RULE
  [create_rule(5)].

  Use the DROP VIEW [drop_view(5)] statement to drop views.

  Be careful that the names and types of the view's columns will be assigned
  the way you want. For example,

  CREATE VIEW vista AS SELECT 'Hello World';

  is bad form in two ways: the column name defaults to ?column?, and the
  column data type defaults to unknown. If you want a string literal in a
  view's result, use something like

  CREATE VIEW vista AS SELECT text 'Hello World' AS hello;

  Access to tables referenced in the view is determined by permissions of the
  view owner. However, functions called in the view are treated the same as
  if they had been called directly from the query using the view.  Therefore
  the user of a view must have permissions to call all functions used by the
  view.

EXAMPLES
  Create a view consisting of all comedy films:

  CREATE VIEW comedies AS
      SELECT *
      FROM films
      WHERE kind = 'Comedy';

COMPATIBILITY
  The SQL standard specifies some additional capabilities for the CREATE VIEW
  statement:

  CREATE VIEW name [ ( column_name [, ...] ) ]
      AS query
      [ WITH [ CASCADED | LOCAL ] CHECK OPTION ]

  The optional clauses for the full SQL command are:

  CHECK OPTION
       This option has to do with updatable views. All INSERT and UPDATE
       commands on the view will be checked to ensure data satisfy the view-
       defining condition (that is, the new data would be visible through the
       view). If they do not, the update will be rejected.

  LOCAL
       Check for integrity on this view.

  CASCADED
       Check for integrity on this view and on any dependent view. CASCADED
       is assumed if neither CASCADED nor LOCAL is specified.

  CREATE OR REPLACE VIEW is a PostgreSQL language extension.  So is the
  concept of a temporary view.

SEE ALSO
  DROP VIEW [drop_view(5)]

Index for Section VIEW

Alphabetical listing for C

Top of page