Key-Value, Column-Family Stores, and Document-oriented databases
Key-Value, Column-Family Stores, and Document-oriented databases, as they all share several characteristics all have a fundamental data model that is based around a single, rich structure of closely-related data. In the field of software engineering called domain driven design, professionals often refer to this as an "aggregate".
In a 2-3-page paper, select one type of database and research how the term, “aggregate” applies to the design. Include an example of at least one entity relationship.