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Foreign Key

Last updated May 7, 2024

Foreign keys are pivotal in establishing a link between data across different tables. Essentially, a foreign key in one table points to a column in another table, typically the primary key, containing unique values. This setup facilitates a robust cross-referencing mechanism between the tables.

# Example

Consider two tables in a database: Customer and Order. The Customers table has a unique identifier for each customer, known as CustomerID, which serves as its primary key. In the Order table, there’s a column named CustomerID that serves as a foreign key.

This foreign key creates a link to the Customer table, enabling us to trace each order back to the customer who made it. This relationship ensures data integrity and simplifies queries that involve data from both tables.


References: Primary Key, Dimensional Modeling, Surrogante Key
Created 2024-01-20