Gavin King: “If you think that relational technology is for persisting the state of your application, you’ve missed the point. The value of the relational model is that it’s democratic. Anyone’s favorite programming language can understand sets of tuples of primitive values. Relational databases are an integration technology, not just a persistence technology. And integration is important. That’s why we are stuck with them.”
Amen to that. If there’s one thing that we need to learn is that data lives much longer than applications.
“ORM makes it easy to work with objects and databases most of the time. Compared to five or six years ago, ORM has solved most of the problems of data access in online applications. It is no longer anywhere near as painful as it used to be.”
I have to admit I haven’t been using Hibernate or any other ORM solution for the past year or more, but some of the pain is still there, and sometimes the pain makes you think that you’d be better off with plain, old SQL rather than a full-fledged ORM.
In any case, there is probably something that is even more painful than either plain SQL, an ORM or an object database: it’s using RDF as a persistent storage medium just because it’s more flexible than a RDBMS. Trust me, you don’t want to do that ;).
Of course there is still some pain. I guess the whole point of what I’m trying to say is: you can’t magic away the pain of complex problems just by conjuring some silver bullet like OODBMS (or Ruby hehe).
Cheers, Gavin.
The point about relational databases as an integration technology is well made, but I’m curious to know why you consider RDF worse as a storage medium. It has definite advantages over OO/RDBs when it comes to integration on the web (thanks to the use of URIs as keys, and the open world model).
For persistence I can’t see any way it’s worse than OO/RDBs (in fact quite a few RDF stores use RDBs for persistence under the hood). What’s more, RDF has well-defined serializations (such as RDF/XML) which means that not only is the data portable between stores, it can also be dumped in a *standard* form. (For persistence it’s perfectly reasonable to divide the data up into manageable chunks and distribute them across RDF/XML files).
If “data lives much longer than applications”, then isn’t it better to take advantage of a clear standard, rather than the quasi-standards found in SQL implementations, or for that matter the more proprietary models found in OO DBs..?
See also: Shelley Powers on RDF as the Bezoar Stone.