Programming Essentials Python - CRUD Operations - Recap of RDBMS Concepts

Description: This article will guide you through the key concepts of RDBMS (Relational Database Management Systems) and how to perform CRUD (Create, Read, Update, Delete) operations using Postgres. You will learn about normalization, relationships between tables, constraints, and more, with practical examples to help solidify your understanding.

Explanation for the video

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Key Concepts Explanation

RDBMS (Relational Database Management System)

RDBMS is a type of database management system that stores data in a structured format using rows and columns. It ensures data integrity and provides powerful querying capabilities.

    username VARCHAR(50) UNIQUE NOT NULL,


Normalization is the process of organizing data in a database to reduce redundancy and dependency. It ensures each table represents a single theme or entity.

    order_id SERIAL PRIMARY KEY,
    user_id INT REFERENCES users(user_id),
    order_date DATE

Hands-On Tasks

Explore the RDBMS concepts mentioned above and create a sample database structure using Postgres. Perform the following tasks:

  1. Create a database named “ecommerce” in Postgres.
  2. Create tables for “users” and “orders” with appropriate columns and relationships.


In this article, we delved into the key concepts of RDBMS and performed hands-on tasks to apply them using Postgres. Understanding these concepts is essential for efficient database management and querying. Practice these concepts and engage with the community for further learning and collaboration.

Recap of RDBMS Concepts

Let us recap some of the RDBMS concepts before performing CRUD Operations. We will develop programs to interact with Database using Postgres which is RDBMS Database.

  • RDBMS stands for Relational Database Management System.

  • Tables will be normalized to ensure that records are uniquely identifiable, related with each other, etc.

  • Most of the database tables supporting transactional applications are either in 3rd Normal Form or Boyce Codd Normal Form.

  • There are different types of relationships between tables.

    • one to one

    • one to many

    • many to one

    • many to many (typically implemented via bridge tables)

  • Tables typically contain different types of constraints.

    • Primary Key Constraints

    • Unique Key Constraints

    • Not Null Constraints

    • Foreign Key Constraints referencing Primary Key Constraints of its parent table.

    • and more

image.png (Include image of Data Model for Oracle HR Database)

  • Data Model for Cloudera’s Sample Retail Database.

image.png (Include image of Data Model for Cloudera’s Sample Retail Database)

Watch the video tutorial here