A compound key is an example of a primary key - Scottish Highers Computing Science - Question 7 - 2019

A compound key in a relational database refers to a key that consists of two or more attributes (or columns) that together uniquely identify a record in a table. These attributes can be either foreign keys from other tables or primary keys from the same table.

For example, consider a table that stores information about student enrollments. A compound key could be made up of StudentID and CourseID. Here, neither StudentID nor CourseID alone may uniquely identify an enrollment, but when combined, they create a unique identifier for each record.

This ensures that each combination of student and course is distinct, allowing for efficient data retrieval and maintaining data integrity.