How does column-oriented NoSQL differ from document-oriented?

Question

The three types of NoSQL databases I\'ve read about is key-value, column-oriented, and document-oriented.

Key-value is pretty straight forward - a key with a plain value

Answer 1

In "insert", to use rdbms words, Document-based is more consistent and straight foward. Note than cassandra let you achieve consistency with the notion of quorum, but that won't apply to all column-based systems and that reduce availibility. On a write-once / read-often heavy system, go for MongoDB. Also consider it if you always plan to read the whole structure of the object. A document-based system is designed to return the whole document when you get it, and is not very strong at returning parts of the whole row.

The column-based systems like Cassandra are way better than document-based in "updates". You can change the value of a column without even reading the row that contains it. The write doesn't actualy need to be done on the same server, a row may be contained on multiple files of multiple server. On huge fast-evolving data system, go for Cassandra. Also consider it if you plan to have very big chunk of data per key, and won't need to load all of them at each query. In "select", Cassandra let you load only the column you need.

Also consider that Mongo DB is written in C++, and is at its second major release, while Cassandra needs to run on a JVM, and its first major release is in release candidate only since yesterday (but the 0.X releases turned in productions of major company already).

On the other hand, Cassandra's designed was partly based on Amazon Dynamo, and it is built at its core to be an High Availibility solution, but that does not have anything to do with the column-based format. MongoDB scales out too, but not as gracefully as Cassandra.