Which one of the below keys is used to create one-to-many relationship between tables?

1. Primary
2. Composite
3. Foreign
4. Alternate

The correct answer is Foreign. Here’s why:

• A foreign key is a column (or combination of columns) in one table that refers to the primary key in another table.  
• It’s the mechanism that establishes a link between the two tables, specifically a one-to-many relationship.
• In a one-to-many relationship, one record in the “parent” table (the table with the primary key) can be related to multiple records in the “child” table (the table with the foreign key).