Can you explain what ForeignKey means in a database?

ForeignKey is a field in a database table that references the primary key of another table. It is a mechanism to establish a relationship between tables and ensure data integrity.

For example, if there is an Orders table and a Customers table, then in Orders there can be a customer_id field, which is a foreign key pointing to a specific customer in the Customers table.

Using ForeignKey allows:

• Guarantee that the reference to another table exists (for example, you cannot create an order for a non-existent customer).
• Ensure cascading updates or deletions of related records.

Thus, ForeignKey helps model relationships between entities and maintain data integrity in a relational database.