Important questions

What type of datastore is this ?

• relational

• key-value

• columnar

• document-oriented

• graph

What was the driving force ?

• RDBMS databases arose in a world where query flexibility was more important than flexible schemas

• Column-oriented datastores were built to be well suited for storing large amounts of data across several machines, while data relationships took a backseat

How do you talk to it ?

• command line interface

• script

• graphical interface

What makes it unique ?

• querying on arbitrary fields

• indexing for rapid lookup

• some support ad hoc queries; For others, queries must be planned

• Is schema a rigid framework enforced by the database or merely a set of guidelines to be renegotiated at will

How does it perform ?

• Does it support sharding

• What about replication?

• Does it distribute data evenly using consistent hashing, or does it keep like data together ?

• Is this database tuned for reading, writing, or some other operation ?

• How much control do you have over its tuning

How does it scale ?

• Talking about scalability without the context of what you want to scale to is generally fruitless

• Whether each datastore is geared more for

• horizontal scaling (MongoDB, HBase, Riak),

• vertical scaling (Postgres, Neo4J, Redis),

• something in between