Question: In relational database design, what is a primary key?

Wed, 29 Apr 2026 18:03:39 +0000

# What Is a Primary Key in Relational Database Design? In relational database design, the primary key is a fundamental concept that plays a crucial role in ensuring data integrity, uniqueness, and efficient data management. Understanding what a primary key is—and why it matters—helps developers and database architects build robust, reliable systems. ## Definition of a Primary Key A primary key is a column (or a set of columns) in a table that uniquely identifies each record in that table. It ensures that no two rows have the same key value, thereby enforcing entity integrity—one of the core principles of relational database design.