MapServer, PostGIS, Subquery with JOIN, WMS GetFeatureInfo / Followup Question
Jeff Hoffmann
jeff at PROPERTYKEY.COM
Fri Feb 24 05:09:22 PST 2006
Nick Floersch wrote:
>
>
> ------------------------------------------------------------------------
> *From:* Nick Floersch
> *Sent:* Friday, February 24, 2006 5:03 AM
> *To:* Nick Floersch
> *Subject:* RE: MapServer, PostGIS, Subquery with JOIN, WMS
> GetFeatureInfo / Followup Question
>
> After my just previous post to the list, I decided to try my alternative
> solution...
>
> "" Before anyone suggests the solution of using a view to encapsulate
> my JOIN so it need not be in the subquery, I'll just say that I am aware
> I could try that approach (though I have not yet done so), but
> my curiosity has been piqued by this problem as it is, so I'm hoping to
> find out more about the JOINs in subqueries issue I have. I would also
> really love to know how MapServer gets the attribute columns for PostGIS
> layers. ""
This is on my "figure out some day myself" list, too. I'm doing the
view thing right now, but I'd like to not have to create views for
everything.
> ---snip---
>
> The only thing I can think of is... does the PostGIS connector require
> the table to have OIDs? It looks that way.
Yes. It needs some unique field in order to randomly access an
individual rows, it just so happens that OID is a convenient way to get
that in most cases. You can also specify your own unique column name
with "using unique <column name>" if your view doesn't have an OID
column but you have some other key you can use. I just pull in the OID
from the main geometry-containing table when I define the view.
--
Jeff Hoffmann
jeff at propertykey.com
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