What is secondary index in MongoDB?

Related questions

1. What is Upsert in mongoose?
2. What is timestamp in MongoDB?
3. Can we create primary key in MongoDB?
4. Is the method used to limit the records in MongoDB?
5. When we use merge in SQL?
6. What is Upsert Salesforce?
7. What is Mongoose for Mongodb?
8. What is projection in MongoDB?
9. What is merge into SQL?
10. What is difference between Upsert and update?

Tags

1. #create
2. #speeding
3. #allows
4. #feature
5. #simple
6. #collections
7. #supports
8. #indexes
9. #operations
10. #complex
11. #queries
12. #aggregates
13. #sorts
14. #different
15. #secondary
16. #mongodb
17. #finds
18. #compared
19. #document
20. #matches
21. #store
22. #other