Question

Use the following data model for this question: animal animal id name adopter adopter id name animal adopter animal adopter id animal id adopter id which of the following is a situation where an outer join could be useful?

a.) when a pet adoption agency wants to see only animals that have not been adopted
b.) when a pet adoption agency wants to see all animals, including those that have been adopted and those that haven't
c.) when a pet adoption agency wants to see all people who have adopted animals from the agency
d.) when a pet adoption agency wants to see only animals that have been adopted

Answer 1

An outer join is useful when a pet adoption agency wants to see all animals, both adopted and not adopted, to track every animal regardless of adoption status.

Step-by-step explanation:

The situation where an outer join could be useful is:

• b.) when a pet adoption agency wants to see all animals, including those that have been adopted and those that haven't.

An outer join is used in SQL to return all records from one table and the matched records from the second table. If there is no match, the result is NULL on the side of the table without a match.

Therefore, in the context of the pet adoption agency data model, using an outer join between the 'animal' and 'animal adopter' tables would provide a complete list of all animals, showing both those with adopters and those awaiting adoption. This is useful for agencies to track every animal, regardless of their adoption status.