What is the Difference between a Primary Key and a Foreign Key in a Relational Database?

In a relational database, a primary key is a column or a set of columns that uniquely identifies each record in a table. It must contain unique values and cannot have NULL values. The primary key helps in maintaining data integrity by ensuring that each record is uniquely identifiable.

On the other hand, a foreign key is a column or a set of columns in a table that establishes a relationship with a primary key in another table. It helps in maintaining referential integrity by ensuring that data remains consistent across tables.

How are Primary and Foreign Keys Used to Maintain Data Integrity and Ensure Relational Database Consistency?

Primary keys help in maintaining data integrity by enforcing entity integrity, ensuring that each record in a table is unique and identifiable. Foreign keys, on the other hand, help in ensuring referential integrity by establishing relationships between tables and preventing orphaned or inconsistent data.

By using primary keys and foreign keys in a relational database, data integrity is maintained through the enforcement of unique and consistent relationships between tables. This ensures that the data remains accurate and reliable, contributing to the overall consistency and reliability of the relational database.