🎥 Lecture 1: Relational Model Constraints (मर्यादा) Introduction

🎯 Learning Objectives (उद्दिष्टे)

By the end of this lesson, you will be able to:

• Explain referencing between entities.
• Differentiate between a Primary Key and a Foreign Key.
• Identify a Parent Table and a Dependent Table.

🧩 Concept Overview

In relational databases, data must follow certain rules or constraints to maintain accuracy and consistency. These are called relational model constraints.

Using the Book–Author example:

• At least one author writes one book → a one-to-one relationship.

• To look up Author information, the Book entity refers to Author.

• To look up Book information, the Author entity refers to Book.

  This cross-reference process is called Referencing.

🔗 Key Concepts and Terminology

1. Referencing

When one table refers to another to fetch related data.

In relational databases, referencing ensures data integrity (अखंडता) between two relations.