Randy, We have already indicated that we store indexed blobs. We can store these blobs as XML, DADL or Binary. It doesn't matter, it is just a serialisation format and the "MAGIC" happens in the object layer. Another benefit of this is that it obfuscates the EHR content forcing the data access through the EHR Server to ensure that the semantics and security of the content is maintained. This is a deterrent to traditional application developers bypassing these important EHR requirements.
Regards Heath Heath Frankel Product Development Manager Ocean Informatics Ground Floor, 64 Hindmarsh Square Adelaide, SA, 5000 Australia ph: +61 (0)8 8223 3075 mb: +61 (0)412 030 741 email: heath.frankel at oceaninformatics.com <mailto:heath.frankel at oceaninformatics.biz> From: [email protected] [mailto:openehr-technical-bounces at openehr.org] On Behalf Of Randolph Neall Sent: Thursday, 8 November 2007 1:26 AM To: erisu at imt.liu.se; For openEHR technical discussions Subject: Re: OpenEHR queries Erik, as I ask my questions about the Ocean system, I'm getting the growing sense, perhaps mistaken, that I'm pushing against trade secrets. Have they told me as much as they're going to? If they're storing the real guts of their clinical information as blobs ("low-level" blobs, as Tom implies, which could be mere binary serializations of their objects) then it would seem querying would be an interesting issue. I assume Ocean is the premier implementation of openEHR, what with its ultimate champion in Tom Beale, and if they've had to go this route, this would be significant. Tom works there, and I'm assuming that what he says reflects how they do it. If they had all their data in MS Sql tables and columns, not blobs, and it worked well that way, I doubt Tom would be inveighing against relational databases for clinical data. Maybe they've got some serious magic in play. Randolph On 11/7/07, Erik Sundvall <erisu at imt.liu.se> wrote: On 11/7/07, Randolph Neall <randy.neall at veriquant.com> wrote: > Can I assume that what Thomas here advocates, ("relational databases can be > used very effectively as a low-level store of blobs keyed by path") is what > how the ocean persistence layer actually works? Beyond this, Thomas > apparently has little use for the capacities of Sql-type RDBMS systems to > handle clinical information. Does the Ocean system ultimately amount to > blobs keyed by paths (presumably string paths)? If so, what kind of blobs, > XML blobs, or some other structured text system? A guess from someone outside Ocean: If Tom has been involved I'd guess it's stored as blobs of DADL or something similar ;-) not XML... In a master thesis project here some time ago the students used db4o (http://www.db4o.com/) to store openEHR RM objects, but in a rudimetary way mostly as a simple datastore for Java objects. Query was not the focus of that project so they did not test proper advanced querying or scalability using db4o. // Erik _______________________________________________ openEHR-technical mailing list openEHR-technical at openehr.org http://lists.chime.ucl.ac.uk/mailman/listinfo/openehr-technical -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/mailman/private/openehr-technical_lists.openehr.org/attachments/20071108/e3940e94/attachment.html>
