John Ours schrieb:
On Jan 19, 2009, at 2:33 PM, Stavros Panidis wrote:
my customer is a major department in a public hospital. Each time they
decide to perform an experiment and take in account different
measurements. No one can predict this. So they need to have the
ability to create and/or alter existing tables.
Hi Stavros,
We do a lot of similar systems for healthcare and the situation you're
describing is fairly typical, especially when dealing with clinical
data. I agree with Suzanne though, implementing it by changing the
underlying tables is a recipe for trouble. Too many other pieces like
validation, reports, data feeds, data cubes, etc get really complicated
when the schema starts changing and the data gets ragged.
Typically we'd start to model this problem with a metadata structure
like a Procedure entity (the header record), an Aspect entity (things
that can be measured in a procedure, valid ranges, expected data types),
and a ProcedureAspect entity (the value of a given Aspect for a Procedure).
Adding entries to the Aspect table is akin to changing the database
schema...it defines which attributes you expect for a Procedure...and
that's easily done at runtime.
-John
Hi Stavros, John,
funny: our system is for healthcare too ;-)
Our software is for creating, managing and data collection of clinical
studies where the customers can do everything from setup to export on
their own without any programming needed from our side.
There is a lot of advantage of beeing mostly generic, but there are
restrictions too. For example the implementation of "simple" new
features, like a new report, can be more complex than desirable.
Regards,
Susanne
--
Susanne Schneider
Coordinator secuTrial Development
iAS interActive Systems GmbH
Dieffenbachstraße 33 c, D-10967 Berlin
fon +49(0)30 22 50 50 - 498
fax +49(0)30 22 50 50 - 451
mail susanne.schnei...@interactive-systems.de
web http://www.interActive-Systems.de
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Sitz der Gesellschaft: Berlin
Amtsgericht Berlin Charlottenburg, HRB 106103B
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