From: Suman Nath (sknath@cmu.edu)
Date: 01/31/03
Hi James,
You are right.
One way to do what you suggested is not to keep any person element in the
schema and let the senselet send the appropriate XUPDATE command to
add/delete person elements in the appropriate part of the database. For
example, if Jusin Case is at WH, the senselet running at WH SA will send an
XUPDATE command to the WH OA to *add* a person entry for him (and if he is
not at HH, the HH senselet will send an XUPDATE command to delete his, if
there is any, person element at HH OA). In this case, senselet needs to know
the static metadata about the people (you can put that in a configuration
file at SA).
To do that, you also need to know how to use an XUPDATE command to add or
delete elements from the XML database. Since we do not expect you to know
that at this point, you can use the the parking space finder schema as a
model for this mini project (which keeps redundant static data at different
parts of the database, but makes life a bit easier).
Note that, the parking space finder schema did not have any redundant static
metadata.
You are welcometo implement the schema in any way you like. Just remember
that the information in the schema and the informaiton sent by the senselets
should represent the complete global database where the query processing is
done.
- Suman
-----Original Message-----
From: owner-irisnet-course@intel-iris.net
[mailto:owner-irisnet-course@intel-iris.net]On Behalf Of James Newsome
Sent: Thursday, January 30, 2003 3:45 PM
To: irisnet-course@intel-iris.net
Subject: database schema
I'm not sure how to put the database schema together. Using the parking
space finder as a model, the only way seems to be to put the static
information about each person under each location, and have a 'present'
field that the SA sets to yes or no.
However, this seems wrong from a database perspective. i.e. the fact that
Justin Case is a 43 year old faculty should only be in the database once.
The way that makes more sense to me is to have an entry for each person at
the global level, (or maybe the CMU level), and have the SA dynamically
insert and delete entries at their local levels that are just keys
pointing to the rest of the information about that person. Is there a way
to do this in the current infrastructure, or am I heading in the wrong
direction?
Thanks,
Jim
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