Hi, You can't say one is better than the other, they are just different. JCR is more geared towards file systems (which are also hierarchical) and web content (urls, which are also hierarchical). It's easier to map this kind of content into the JCR model than to map it to the relational model. Then, nodes don't have a fixed set of properties. This better matches to the 'object oriented' world than a relational model. It also better matches XML / JSON use cases. JCR has some features that are not / less standardized in the relational world (for example versioning).
> if you're doing a lot of updates or your set modifications are > common, you'll typically find the other models faster, Yes and no. One advantage of the relational model is that it usually better compresses the data because of normalization. But that only applies in the small scale. If the data doesn't fit into one system, other approaches may scale better. That's the reason for Google BigTable, Hadoop, Cassandra, and so on. It also applies to JCR. The current Jackrabbit implementation is not yet 'highly scalable' (that wasn't the goal yet), but the JCR model is. I'm not sure if the relational model does limit the scalability of SQL databases, but current relational database implementations just don't scale very well. Regards, Thomas
