What is the role of primary keys in linking tables?

Primary keys play a crucial role in relational databases by uniquely identifying each record in a table. This uniqueness ensures that no two records can have the same primary key value, which allows for precise retrieval and manipulation of data. When tables are linked through relationships, typically via foreign keys, the integrity of the data is maintained, making it possible to accurately join and query data across different tables.

The uniqueness provided by primary keys is essential for various operations, such as updating records or establishing relationships between tables, as it eliminates ambiguity in identifying which record is being referenced. In practice, every table should have a primary key to ensure that each entry is distinguishable from all others, facilitating efficient data management and integrity throughout the database system. This identification process is foundational to the structure of relational databases and enhances the reliability and usability of the data stored within.