A short note on database design process

Step - 1
Requirements Gathering

Understanding what you want to do, and what you have is essential before you can dive into designing a database.

Step - 2
Conceptual Design

We specify the entities, columns, and their relationship. We may use an entity relationship (ER) diagram to visualize the database.

The output is: A conceptual schema (described using a conceptual data model like ER model).

Step - 3
Logical Design

It’s concerned about data model mapping; mapping a conceptual schema (like ER model) into logical schema to provide a much detail description.

The output is: A logical schema (described using a logical data model specific to the DBMS like relational model).

Step - 4
Physical Design

It describes the details of how data is stored. You start by defining (already modeled) tables, how the data is stored, define relationships, … in DBMS.
This requires dealing with the DBMS, and could involve SQL.

The output is: An internal (physical) schema (described using a physical data model).