Lists Home |
Date Index |
10/18/2002 7:25:48 PM, "Elizabeth Hinson" <email@example.com> wrote:
> Which is better (for medical data)?
> Native XML database
> XML-enabled relational database?
In the immortal words of somebody or other, "it depends."
You should definitely start by reading
We had a nice thread on a "decision tree" to make this kind
of choice about a year ago. See the thread starting at
As a very general rule of thumb, the more "document-like" your
XML, the less suitable it is likely to be for RDBMS-based storage.
(Whether the current XML features from the RDBMS vendors count
as "RDBMS-based storage" is not entirely clear to me.
My biased and non-expert opinion is that medical
data tend to be "semi-structured" (having both "document" and "data"
information) and have historically been difficult
to manage effectively in RDBMS systems. Wrapping the data in
XML syntax doesn't change that fact.
Another major consideration is whether you have an existing RDBMS
system and want to add XML capabilities, or whether you are starting
from a clean slate and only want to handle XML. In the former situation,
it is much harder to make the case for a native XML DB than in the
On a related point, it depends very much on whether your other tools
handle XML natively and whether your developers expect to use XML idioms
such as XPath/XQuery, or RDBMS idioms such as SQL. The whole point of a native
XML database management system is to use XML idioms to define database
schema, perform queries, manipulate data with APIs, etc.
For better or worse, the distinction between "native XML" and
"XML-enabled" is increasingly fuzzy as far as actual products go.
You really need to compare the features, limitations, long term and
short term costs, and ease of application development for actual products.
Ron Bourret's companion article at
lists them, and it looks like it was recently updated.