Explain what is Aggregation?
Aggregation: Aggregation is an significant concept in database design whereas composite objects could be modelled during the design of database applications. Thus, preserving the aggregation concept within database implementation is must. we propose models for implementation of aggregation in an Object-Relational Database Management System (ORDBMS) through the use of index clusters and nested tables. Aggregation refers to an abstraction in that a relationship among objects is regarded as a higher-level object.