patrick.dowler at nrc-cnrc.gc.ca
Fri Nov 3 10:32:28 PST 2006
On Friday 03 November 2006 02:21, Kona Andrews wrote:
> Message from Jeff follows.
> The problem with Region is that everything I've seen about Region so far
> gives no details of what table(s) is/are involved or what columns will
> be involved in the search! Tables have to be inferred from the context,
> and columns by the implementation. I suspect the implementation will
> decide whether this is healpix, htm or plain ra & dec. But if the
> latter, what if there is more than one column that can be construed as
> ra (or dec)? With tables, I assume with the current region spec, that
> region will be applied to each table in the query.
I completely agree that this is a serious issue. I had wanted to suggest we
put off disucssing region until after deciding what else was in - mainly
because once you have JOIN you easily get to the case where the result table
to be filtered by region has multiple sets of columns that correspond to
from observation o join source s on o.obsID = s.obsID
where o.foo = X and s.mag > Y and region(...)
OK - does the source have to be in the region? the center of the observation?
The result will be quite different of someone specifies a small region away
from the center of the observation. We really need to specify which table (at
least) and which columns within the table (more explicit) you want the region
to apply to.
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