Nested table rows are stored in a separate table identified through
a hidden NESTED_TABLE_ID by Oracle. Typically, VARRAYs are used when an entire
collection is being retrieved and nested tables are used when a collection is being queried,
particularly if the collection is large and only a subset is needed.
Object-Oriented Development | 321
An application can call object methods through SQL, PL/SQL, Pro*C/C++, Java,
OCI, and the Oracle Type Translator (OTT). The OTT provides client-side mappings
to object types by generating header files containing C structure declarations
and indicators. Developers can tune applications by using a client-side object cache
to improve performance.
Inheritance, or the use of one class of objects as the basis for another, more specific
class, is one of the most powerful features of object-oriented design. The child class
inherits all the methods and attributes of the parent class and also adds its own
methods and attributes to supplement the capabilities of the parent class. The great
power of inheritance is that a change in a parent class automatically ripples down to
the child classes.
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