What Is an Entity?
Basically, each entity is a piece of information that you need to be able to save and use in the database. Establishing entities is a critical step in the database design process because it is always tougher to add another type of information to the database schema later on. Typical entities in a retail business, for example, will include customer name, store number, product ID, product price, and so on.
What’s The Meaning of a Relational Database?
A relational database allows you to see the interaction between the various entities. For example, if the primary key in your table is the Customer ID, a relational database allows you to compare that customer’s products based in a unique Customer ID number found in the products table. Under the products table, the Customer ID number is considered as a foreign key.
In this case, based on the foreign key, we link all the products to the specific customer. This capability allows a report to draw all information off of the products table to let you know what products the customer has purchased and perhaps even the quantity, the price they paid, or the location the purchase was made at (depending on the information listed on the products table).