Question

A(n) ________ is a foreign key in one table that does not have a matching value in the primary key field of a related table.

1) duplicate key
2) wildcard
3) composite key
4) orphan

Answer 1

An orphan is a foreign key in one table with no matching primary key in a related table, which can compromise database integrity.

Step-by-step explanation:

A foreign key in one table that does not have a matching value in the primary key field of a related table is known as an orphan. In relational databases, referential integrity is a constraint that ensures that relationships between tables remain consistent. When there is an orphan record, it means that there is a reference to a primary key value that no longer exists or is never created in the related table. This situation can cause issues in database integrity and often occurs when records in the primary table are deleted without properly handling the related records in the foreign key table.