Schemaless databases allows you to model your data in a way that is more natural to your domain. The table-relational model used by SQL databases isn't always s

Schemaless databases allows you to model your data in a way that is more natural to your domain. The table-relational model used by SQL databases isn't always suitable for all types of data, most notably trees and graphs. Don't get me wrong, I'd probably pick a traditional RDBMS over MongoDB for most projects, but the object-relational impedance mismatch is a real problem.