title: What NoSQL database (categories) support versioning?
body: <p>I thought that regardless of whether a NoSQL aggregate store is a key-value, column-family or document database, it would support versioning of values. After a bit of Googling, I'm concluding that this assumption is wrong and that it just depends on the DBMS implementation. Is this true?</p>
  
  <p>I know that Cassandra and BigTable support it (both column-family stores). It SEEMS that Hbase (column family) and Riak (Key-Value) do but Redis and Hadoop (Key-Value) do not. <strike>Mongo DB (document) does</strike>Couchbase does but MongoDB does not (document stores). I don't see any pattern here. Is there a rule of thumb? (for example, "key value stores generally do not have versioning, while column-family and document databases do")</p>
  
  <p>What I'm trying to do: I want to create a database of website screenshots from URL to PNG image. I'd rather use a key-value store since, versioning aside, it is the simplest solution that satisfies the problem. But when website changes or is decomissioned and I update my database I don't want to lose old images. Even if I select a key-value database that has versioning, I want to have the luxury to switch to a different key-value database without the constraint that many key-value DBs do not support versioning. So I'm trying to understand at what level of sophistication in the continuum of aggregate NoSQL databases does versioning become a feature implicit to the data model. </p>