Database Systems: ORDB Methods and Inheritance

To implement the behavior of objects.

Methods written in PL/SQL or Java are stored in the database, whereas those written in other languages like C are stored externally.

To denote the object instance on which the method is currently being invoked.

To define the implementation of the member methods declared in the type definition.

By creating a table of the custom data type using a CREATE TABLE statement.

The method can reference the attributes of the object instance without using a qualifier.

UNDER

They must have different names from the attributes or methods in all its supertypes in the type hierarchy.

Create a table with the type as its data type, and specify the primary key as desired, e.g. Create table person_tab of person_type (pid primary key);

Use the INSERT INTO statement with the subtype constructor, e.g. INSERT INTO person_tab VALUES (student_type(4, 'Edward Learn', '65 Marina Blvd, Ocean Surf, WA, 6725', 40, 'CS'));

VALUE() function

The new subtype inherits all the attributes and methods of its parent type, both declared and inherited.

It must be called repeatedly and can only compare two objects at a time.

To return the count of projects associated with an employee.

It reduces redundancy and increases flexibility and extensibility.

It specifies the storage of the nested table.

A subtype inherits from a supertype, which is a parent base type.

To create user-defined types that can be used to define tables and objects.