What does a foreign key represent in data modeling?

What does a foreign key represent in data modeling?

• A. A unique identifier for an entity
• B. A link between two entities
• C. A property of an entity
• D. A type of entity

Answer: (B)

A foreign key represents a link between two entities in data modeling. This is a fundamental concept in relational databases, where a foreign key is a field (or a collection of fields) in one table that uniquely identifies a row of another table. Essentially, it establishes a relationship between the tables, ensuring referential integrity. When one table has a foreign key that references the primary key of another table, it means that the data in the foreign key column is directly related to the data in the primary key column of the parent table. This structure allows for the organization of data across different tables and enables complex queries to pull related data efficiently. By using foreign keys, you create relationships that help define how data in one table correlates with data in another, supporting tasks like data retrieval, join operations, and data consistency across the database. In the context of data modeling, understanding foreign keys is essential as they play a crucial role in designing databases that accurately represent real-world entities and the relationships among them.

A foreign key represents a link between two entities in data modeling. This is a fundamental concept in relational databases, where a foreign key is a field (or a collection of fields) in one table that uniquely identifies a row of another table. Essentially, it establishes a relationship between the tables, ensuring referential integrity.

When one table has a foreign key that references the primary key of another table, it means that the data in the foreign key column is directly related to the data in the primary key column of the parent table. This structure allows for the organization of data across different tables and enables complex queries to pull related data efficiently. By using foreign keys, you create relationships that help define how data in one table correlates with data in another, supporting tasks like data retrieval, join operations, and data consistency across the database.

In the context of data modeling, understanding foreign keys is essential as they play a crucial role in designing databases that accurately represent real-world entities and the relationships among them.