Feasel’s Law

I’ve had this idea on my mind for a while and figured I’d might as well write it down…

Feasel’s Law – Any sufficiently advanced data retrieval process will eventually have a SQL interface.

This is a bit tongue-in-cheek, but it plays out pretty well; typically, a major sign of database maturity is its reimplementation (at least in part) of SQL.  Examples:

• Hadoop started out as writing map-reduce jobs in Java.  Yahoo then created Pig to work with ETL processes.  After that, Facebook created Hive, an implementation of SQL for Hadoop.
• Spark started out using Java and Scala, and then Python.  Not too long after, we had Shark and then Spark SQL.
• HBase is a NoSQL database on top of Hadoop.  Now we have Phoenix, which is a SQL interface to HBase.
• The primary methods of operation with Cassandra are SQL-like statements.
• Riak TS has a SQL interface.  Incidentally, I love the author’s comment that SQL isn’t dead yet…
• The easiest way to access CosmosDB data?  SQL.  That interface isn’t fully baked yet—it doesn’t allow grouping, for example—but it’s getting there.

One of the few strong counter-examples is MongoDB, which doesn’t have a SQL interface but does have a SQL translation guide.  DynamoDB also does not offer a SQL interface, though there are third-party interfaces and management tools which give you the same effect.

Otherwise, if you’re using a database that was created after 1990, has any significant user base, and is a mature platform, chances are it’s got a native SQL interface.