CREATE VIEW
  SQL - Language Statements
 
 
  CREATE VIEW
  define a new view
 
 
  CREATE VIEW
 
 
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 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.
  
 
 
  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  or
       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
    .
   
   
    Use the 
    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