Why is it important to have a unique value for each primary key?

Having a unique value for each primary key is crucial for maintaining data integrity and preventing confusion within a database. The primary key serves as a unique identifier for each record in a table, ensuring that each entry can be distinctly referenced and accessed. When every primary key has a unique value, it prevents situations where two records might be mistaken for one another, which could lead to errors in data retrieval, updates, or deletions.

This unique identification helps preserve the accuracy of the data by ensuring that relationships between tables (especially in relational databases) remain clear and unambiguous. Without unique primary keys, it would be challenging to enforce relationships and constraints, which could ultimately compromise the reliability of the entire database system. Hence, maintaining uniqueness for primary keys is vital for effective database management and integrity.