Foreign Keys

What is a foreign key in a database?

• A foreign key is a unique identifier for each record in a table.

• A foreign key is used to store text data in a database.

• A foreign key is a field that links to the primary key of the same table.

• A foreign key in a database is a field that links to the primary key of another table.

How is a foreign key different from a primary key?

• A foreign key is used to uniquely identify each record in a table, while a primary key links two tables together.

• A foreign key is used for sorting data, while a primary key is used for filtering data.

• A foreign key can have duplicate values, while a primary key must have unique values.

• A foreign key is used to link two tables together, while a primary key uniquely identifies each record in a table.

Why are foreign keys important in database design?

• Foreign keys establish relationships between tables, enforce referential integrity, and ensure data consistency.

• Foreign keys are only necessary for small databases.

• Foreign keys slow down database performance.

• Foreign keys are used for data encryption in databases.

Can a foreign key be NULL?

• Sometimes

• Maybe

• No

• Yes

What happens when you try to insert a value in a foreign key column that does not exist in the referenced table?

• The value is truncated to fit the column size

• Foreign key constraint violation error

• Data automatically gets inserted in the referenced table

• No action is taken

What is the purpose of enforcing referential integrity using foreign keys?

• To automatically update primary keys

• To allow duplicate records

• To increase database performance

• To maintain data consistency and prevent orphaned records.

What are the benefits of using foreign keys in database relationships?

• Foreign keys make data retrieval more complex in database relationships.

• Foreign keys slow down performance in database relationships.

• Foreign keys ensure data integrity, improve performance, and simplify data retrieval in database relationships.

• Foreign keys complicate data integrity in database relationships.

How can foreign keys help maintain data consistency?

• Foreign keys increase the risk of data anomalies

• Foreign keys ensure that data references between tables are valid and consistent, reducing the risk of data anomalies.

• Foreign keys create duplicate data entries

• Foreign keys slow down data retrieval

What are the potential drawbacks of using foreign keys in a database?

• Foreign keys have no impact on query performance

• Foreign keys simplify database design

• Foreign keys can lead to performance issues, data integrity problems, and complexity in record updates or deletions.

• Foreign keys always ensure data consistency