<...> I understand why relational databases were used to build blog engines
and content management systems. For a long time that was all we had. However, that's going to change fast. I expect that new systems are going to be developed using pure and hybrid XML databases like Exist and DB2 9. The advantages to a programmer working on such systems are just too compelling to ignore.
Or maybe programmers use these database systems because they work, and work good enough?
One consequence of building on top of native XML database rather than a relational database is that well-formedness is going to become more important, not less. In fact, well-formedness is going to become essential because these systems cannot store anything less than a fully well-formed XML document. I predict that this, if nothing else, is going to convince blog engines and content management systems to start fixing up malformed content before storing it. Maybe all the legacy systems won't convert, but the new ones most certainly will.
In other words this means, that John Doe will have more headache with such system, which will be pretty compelling reason to stick with "old-fashioned" RDBMs which "just work". In short - I don't share your vision of the bright future of XML DBMS. Time will show. Regards, Rimantas -- http://rimantas.com/
