Minutes from the meeting of 4/16

Attending: Serge,Roy,Vasilis,Jason,Yue, Michael,Janet

From Roy:
Here's a quick summary of the OEM view application discussion.

* Last week, we talked about using views to impose some regular
structure over an OEM database.  We essentially came up with two
different models. One would use Lore as is, essentially feeding
restructured data into a relational/oo system (or front end).
Alternatively, in a model where Lore is tightly integrated into an OO
or SQL3 system, we wouldn't have to perform extra work to take
advantage of the structure.

* Today, we discussed the possibility of adding "with" to the query
language, to provide much of the functionality of views without
necessarily requiring a new workspace or maintenance.  In addition to
the with clause as defined in the view language, Michael proposed
virtual attributes (such as computing age based on birthday). The
semantics of a query involving with is that objects not specified by
the "with" clause are not reachable when traversing the objects
returned by the query.  Serge pointed out that adding presentation
specifications to the query language is yet another possible aspect to
study.

* Views could be useful in Tsimmis, to "pull" some work out of the
wrappers and/or construct a more intelligible view over a database
integrated from many heterogeneous sources.

* We could cook up a spiffy demo based on the current UI, where
different users could visually specify their own view over a large
Web-site based Lore database (such as ESPN). Each user could specify
the subject areas he/she is interested in, and we could show how
updates are propagated/transformed/filtered into the different views.
I think this is very applicable in the current state of the web-- too
much work is required to find the specific information someone is
interested in.

* This begins to look a lot like Whips, though Whips clearly
concentrates on a) heterogeneous sources and b) the relational model.
Perhaps the two can be combined.

* Finally, Serge argued that a demo need not necessarily have maintenance
to be interesting, pointing out that restructuring static data is
still be very useful.  We didn't get around to how to demonstrate
this within an application.

-----------
More problems to be solved: 
1. Implementation: focusing on implementing materialized view with basic
maintenance for now. Major difference from LORE:
	* WITH clause 
	* multiple workspace

2. Come up with a scenario for a demo (ESPN?)

3. Extending the query language
	* adding virtual attributes? 
	* classification
	* adding and hiding attributes

4. maintenance

5. query subsumption

6. query rewrite [later]