Explanation:More selective queries match a smaller percentage of documents. 3. ___________ is used to determine whether a query is a covered query .
A. explainstats()
B. explain()
C. explainall()
D. All of the mentioned
Answer:A
Explanation:More selective queries match a smaller percentage of documents. 3. ___________ is used to determine whether a query is a covered query .
A. explainstats() B. explain() C. explainall() D. All of the mentioned
Explanation:db.collection.explain() provides information on the execution of other operations, such as db.collection.update(). 4. The ________ message is used to update a document in a collection.