|Oracle9i SQL Reference
Release 2 (9.2)
Part Number A96540-01
Conditions, 11 of 13
type condition to test object instances based on their specific type information.
You must have
EXECUTE privilege on all types referenced by
type, and all
types must belong to the same type family.
This condition evaluates to null if
expr is null. If
expr is not null, then the condition evaluates to true (or false if you specify the
NOT keyword) under either of these circumstances:
expris the subtype of one of the types specified in the
typelist and you have not specified
ONLYfor the type, or
expris explicitly specified in the
expr frequently takes the form of the
VALUE function with a correlation variable.
The following example uses the sample table
oe.persons, which is built on a type hierarchy in "Substitutable Table and Column Examples". The example uses the
type condition to restrict the query to specific subtypes: