You can implement business objects that can be stored in your database and queried or retrieved when needed. These business objects may represent people, data warehouses, inventory items, addresses, purchase orders, invoices, or anything else that defines your operational procedures. Traditional scalar types and new object relational data can be saved with unprecedented flexibility with this persistent array type.
Nested tables are perfect for statistical information and tracking purposes.
Nested Tables allow repeating groups of information to be stored directly into an existing table, without requiring keys to be generated for each row of the nested table. Functions for determining the number of nested rows and manipulating them are provided. REFs speed up access to object relational data. References to nested objects are stored with this new data type. The reference for each object is a globally unique identifier, which is called an Object ID in Oracle.