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       CREATE VIEW - define a new view


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


       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. The new query must  generate  the  same
       columns  that  were  generated by the existing view query (that is, the
       same column names in the same order and with the same data types),  but
       it  may add additional columns to the end of the list. The calculations
       giving rise to the output columns may be completely different.

       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  cannot 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.


              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.

              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(7)] or VALUES [values(7)]  command  which  will
              provide the columns and rows of the view.


       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(7)].

       Use the DROP VIEW [drop_view(7)] 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.

       When CREATE OR REPLACE VIEW is used  on  an  existing  view,  only  the
       view’s  defining  SELECT  rule  is  changed.   Other  view  properties,
       including  ownership,  permissions,  and   non-SELECT   rules,   remain
       unchanged.  You  must own the view to replace it (this includes being a
       member of the owning role).


       Create a view consisting of all comedy films:

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


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

       CREATE VIEW name [ ( column_name [, ...] ) ]
           AS query

       The optional clauses for the full SQL command are:

              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

       LOCAL  Check for integrity on this view.

              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.


       ALTER VIEW [alter_view(7)], DROP VIEW [drop_view(7)]