Oracle9i SQL Reference
Release 1 (9.0.1)

Part Number A90125-01
Go To Documentation Library
Home
Go To Product List
Book List
Go To Table Of Contents
Contents
Go To Index
Index

Master Index

Feedback

Go to previous page Go to beginning of chapter Go to next page

Functions, 149 of 166


TREAT

Syntax

treat::=


Text description of functions97a.gif follows
Text description of treat

Purpose

Use the TREAT function to change the declared type of an expression.

You must have the EXECUTE object privilege on type to use this function.

Examples

The following example uses the table oe.persons, which is created in "Substitutable Table and Column Examples". That table is based on the person_t type, which is created in "Type Hierarchy Example". The example retrieves the salary attribute of all people in the persons table, the value being null for instances of people that are not employees.

SELECT name, TREAT(VALUE(p) AS employee_t).salary salary 
   FROM persons p;

NAME                          SALARY
------------------------- ----------
Bob
Joe                           100000
Tim                             1000

You can use the TREAT function to create an index on the subtype attributes of a substitutable column. For an example, see "Indexing on Substitutable Column Examples".


Go to previous page Go to beginning of chapter Go to next page
Oracle
Copyright © 1996-2001, Oracle Corporation.

All Rights Reserved.
Go To Documentation Library
Home
Go To Product List
Book List
Go To Table Of Contents
Contents
Go To Index
Index

Master Index

Feedback