[erlang-questions] Conceptual questions on key-value databases for RDBMs users

Richard O'Keefe <>
Fri Nov 5 00:26:31 CET 2010


On 5/11/2010, at 11:01 AM, Joe Armstrong wrote:
> I'm no database expert so don't quote me here ...
> 
> As far as I am concerned traditional databases like SQL suffer
> from the fact that the data stored in an individual column is incredible
> simple - I can store an integer/string/... in a column but these are
> incredibly simple data structures.

See Date & Darwen "The Third Manifesto".

They are nearly as incandescently cross about SQL as E. F. Codd was.
Indeed, one of their criteria for a good relational data base is
"not SQL".

The *relational model* makes sense with arbitrarily complex data
values in attributes.  (Date & Darwen explain how this statement
is compatible with 1NF.)

> I want to store and retrieve incredibly
> complicated things - how do I store an XML parse tree in a single cell
> of a database? - How do I store a database in a database ...

There was a lot of work done on "nested relational databases" at
RMIT.  At least three (Atlas, Titan, Titan+) were developed.  I
have no idea what happened to them.  For that matter, I don't know
what Alan Kent is up to these days.  One of the systems was used
to hold and efficiently search large amounts of SGML data.

I note that http://xml.apache.org/xindice/ describes
"Apache Xindice ... a database designed from the ground up to store XML
data".  So SQL and K-V are not the only alternatives around.
(I'm *sure* I remember another free XML database...)




More information about the erlang-questions mailing list