Abstract Data Types (User-Defined Types):

An abstract data type or User-defined datatypes use Oracle built-in datatypes and other user-defined datatypes as the building blocks to model the structure and behavior of data in applications. A User-Defined Datatypes can be categories into two types based on the number of data it can contain. The two types are as follows:

• Simple Object Types
• Collection Object Type

Simple Object Types:

They are implemented by using Abstract Datatypes. These datatypes describe the structure of a datatype that can be embedded as another datatype for a column.