Foreign Key
A foreign key creates a linkage between two tables in the database. It is a field in one table that consists of the primary key of another table. Foreign keys are used to preserve the referential integrity of related entities across different tables by enforcing their relationships.
As an illustration, on a university database, the “Course” table’s foreign key might refer to the primary key of the “Professor” table. This interaction guarantees that each class is related with a valid professor from the existing professor records.
What is an Extension of Entity Type?
Entity Type Extensions are a key issue with a database management system (DBMS) that helps to develop the current entity types without messing with the main structure.
In this article, the definitions, examples, and the importance of the entity type extensions in the database design will be discussed presenting how they are essential to the maintenance of a non-contradictory and efficient data structure and the ability to adapt to the enterprise performance needs that are continuously changing.