What is the role of a Foreign Key in a database?

A Foreign Key plays a crucial role in establishing and enforcing relationships between tables in a database. Essentially, it is a field (or a collection of fields) in one table that uniquely identifies a row of another table or the same table. By doing so, a Foreign Key helps maintain referential integrity within the database, ensuring that the data remains consistent and accurate across related tables.

For example, in a database of an insurance company, a "customer" table might have a Foreign Key that refers to the "policy" table. This allows the system to link customers with their respective insurance policies, facilitating complex queries and maintaining an organized data structure.

This relationship also allows for cascading actions, such as deletion or updates. If a record in the parent table (the table with the primary key) is updated or deleted, the Foreign Key ensures that any corresponding records in the child table are also updated or deleted accordingly, thus preserving data integrity.

The other options do not accurately describe the role of a Foreign Key. Storing large amounts of data is more related to data types and storage capabilities. Increasing query performance pertains to indexing and optimization techniques, while acting as a temporary storage area is unrelated to the fundamental purpose of Foreign Keys.