/usr/man2/cat.l/create_view.l.Z

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 mate-
       rialized. 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.  Tempo-
              rary 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 speci-
              fied 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  query  (that  is,  a SELECT statement) which will provide the
              columns and rows of the view.

              Refer to SELECT [select(l)] for  more  information  about  valid
              queries.

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(l)].

       Use the DROP VIEW [drop_view(l)] 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 func-
       tions 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  sat-
              isfy 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. CAS-
              CADED 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(l)]

SQL - Language Statements         2005-11-05                     CREATE VIEW()