What is the purpose of a foreign key field in a data model?

The purpose of a foreign key field in a data model is to store a reference to a related object. This is crucial in relational database design, as it establishes a linkage between tables by pointing to the primary key in another table. This relationship allows for the organization of data in a way that minimizes redundancy and maintains data integrity. By using foreign keys, one can easily retrieve related data, perform joins, and enforce referential integrity, which ensures that relationships between records are maintained and that orphaned records do not occur in the database.

This design facilitates complex queries and helps maintain a structured and coherent database, ultimately enhancing data management and retrieval processes within applications. The foreign key, therefore, plays a foundational role in supporting the relational model of data organization.