HP 3000 Manuals

Up and Running with ALLBASE/SQL

Creating Views 

When you need to perform a query frequently, you can define a view that
incorporates the column list and the predicate; then you can select from
the view with a simpler command.

As an example, create a view of the Albums and Titles tables that
includes all selections:

     isql=> CREATE VIEW Selections AS Return 
     > SELECT AlbumTitle, Selection, Return 
     > Composer FROM Albums, Titles Return 
     > WHERE Albums.AlbumCode =  Return 
     > Titles.AlbumCode; Return 

Now use the following simple SELECT statement to display all selections
by Palestrina:

     SELECT * FROM Selections Return 
     > WHERE Composer = 'Palestrina'; Return 

Views are useful when you want to define specific subsets of data that
are frequently used or when you want to restrict access to particular
subsets.  You can create views and grant access to them, then revoke
access to the underlying base tables.

Did you remember to COMMIT WORK? This makes the view definition permanent
in the DBEnvironment.

For more information about views, see the CREATE VIEW command in the "SQL
Queries" chapter of the ALLBASE/SQL Reference Manual.

MPE/iX 5.0 Documentation