What is Data Aggregation?
Aggregation in DBMS (Database Management System) is a process of combining two or more entities to form a more meaningful new entity. This Aggregation process is done when the entities don’t make sense on their own without applying the aggregation process. To create aggregation between two entities, which cannot be used for their individual qualities, a relationship is established and the resulting product is created into a new entity.
How does Data Aggregation work?
The relationship can be of any type, such as SUM, AVG, AND, OR, etc. Aggregation on tables can be performed using various tools available in the market.
A manager not only manages the employee working under them but he has to manage the project as well. In such a scenario if entity “Manager” makes a “manages” relationship with either “Employee” or “Project” entity alone then it will not make any sense because he has to manage both. In these cases, the relationship of two entities acts as one entity. In our example, the relationship “Works-On” between “Employee” & “Project” acts as one entity that has a relationship “Manages” with the entity “Manager”.