First, you will learn some basic data-modeling concepts and how current data models developed
from earlier models. Tracing the development of those database models will help you
understand the database design and implementation issues that are addressed in the rest
of this book. In chronological order, you will be introduced to the hierarchical and network
models, the relational model, and the entity relationship (ER) mode1.You will also learn about
the use of the entity relationship diagram (ERD) as a data-modeling tool and the different
notations used for ER diagrams. Next, you will be introduced to the object-oriented model
and the object/relational mode1.Then, you will learn about the emerging NoSQL data model
and how it is being used to fulfill the current need to manage very large social media data
sets efficiently and effectively. Finally, you will learn how various degrees of data abstraction
help reconcile varying views of the same data.