Derived Classes - Teradata Meta Data Services

Teradata Meta Data Services Programmer Guide

Teradata Meta Data Services
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Derived Classes

A derived class is similar to a view in a Teradata Database. It allows you to create a logical class using properties that exist in already defined classes.

To understand the value provided by a derived class, look at the metamodel defined in Figure 6.

Figure 6: Derived Class Sample Metamodel

Using the metamodel in Figure 6, you can get a collection of ViewColumn objects with a name beginning with “customer” using one API call.

What if you also want your search for ViewColumn with a name beginning with “customer” to get the names of the subjectarea and view associated with each ViewColumn object? How can you perform this task with a single API call?

The solution is to create a derived class. A derived class creates a pseudo class that contains the properties of a base class plus properties of related classes. A read of a derived class object will return all properties (base and derived) and searches can be performed on all of the properties of the derived class.