Whenever you come into contact with data that is stored in a database, you need to learn how to retrieve the data, how to add new data and how to modify and delete existing data from the tables in a database.

These tables or entities are set up in a certain way, they have connections with one another.

Before we even start to create the tables, unless they are already there, we need to have a design. We need to think of what tables we need, what are the column names and their values, and what are the keys and how they relate to other tables.

We can make this design using ERD. ERD is there to help design a database.

If you are a developer or an aspiring developer, who will inevitably work with databases at some point, then it is good to know how to design a database system. Needless to say, a database designer needs to know this as it is their job to create database systems.