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I think this is a good idea, but I might offer that the first thing I thought of when seeing ‘generated’ is ’simulated/synthetic data’.</div>
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The only things I could offer as alternatives, in order of quality, I think are:</div>
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“computed”</div>
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“derived”</div>
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“dynamic”</div>
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The problem with all three of those is something that we run into with a number of things in TAP_SCHEMA, which is the distinction between whether we’re actually describing the data or what a user can meaningfully do with it. </div>
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If it’s about the data, the above might be a hair better. But if it’s simply about whether a user can
<i>filter</i> on the data, might I suggest just, <b>filterable</b> ?</div>
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<b>From: </b>registry <registry-bounces@ivoa.net> on behalf of Patrick Dowler via registry <registry@ivoa.net><br>
<b>Date: </b>Wednesday, April 15, 2026 at 9:59 AM<br>
<b>To: </b>dal@ivoa.net <dal@ivoa.net>; registry@ivoa.net <registry@ivoa.net><br>
<b>Subject: </b>Re: "generated" as column/param flag<br>
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<div class="PlainText" style="font-size: 11pt;">External Email - Use Caution<br>
<br>
+1 for generated<br>
--<br>
Patrick Dowler<br>
Canadian Astronomy Data Centre<br>
Victoria, BC, Canada<br>
<br>
On Wed, 15 Apr 2026 at 06:40, Markus Demleitner via dal <dal@ivoa.net> wrote:<br>
><br>
> Dear DAL, dear Registry,<br>
><br>
> In the TAP issue <a href="https://urldefense.com/v3/__https://github.com/ivoa-std/TAP/issues/11__;!!CrWY41Z8OgsX0i-WU-0LuAcUu2o!0NPj16JCZWyKwR44NKUjCNd3yTmk4xa5nGeafwhnWMJ2zaY9IP9iT2W05dVfpQOL6AlqgKUYQIyYVKUBsg$" data-outlook-id="982be084-3f68-47a3-848f-f2f589eaf758">
https://urldefense.com/v3/__https://github.com/ivoa-std/TAP/issues/11__;!!CrWY41Z8OgsX0i-WU-0LuAcUu2o!0NPj16JCZWyKwR44NKUjCNd3yTmk4xa5nGeafwhnWMJ2zaY9IP9iT2W05dVfpQOL6AlqgKUYQIyYVKUBsg$</a> , Pat and I<br>
> found that it would be really desirable to align the flags (indexed,<br>
> std, principal, primary, nullable) we have for columns (in<br>
> TAP_SCHEMA.columns) and TableParam-s (in VODataService tablesets).<br>
><br>
> The immediate occasion was that we should have a way to signal "What<br>
> you see on output in here is not necessarily what is in the database"<br>
> or, in effect, "you cannot write constraints against this column".<br>
> The classic use case from my end is that for most access_urls, DaCHS<br>
> stores a relative path and produces an appropriate URL based on where<br>
> it thinks it is running. But there are many other use cases as well.<br>
><br>
> To address that, I am proposing a flag in the sense of TAP issue #11<br>
> for VODataService given it is nearing PR/RFC:<br>
> <https://urldefense.com/v3/__https://github.com/ivoa-std/VODataService/pull/17__;!!CrWY41Z8OgsX0i-WU-0LuAcUu2o!0NPj16JCZWyKwR44NKUjCNd3yTmk4xa5nGeafwhnWMJ2zaY9IP9iT2W05dVfpQOL6AlqgKUYQIxwclF2vw$ >.<br>
><br>
> We were thinking about a good literal for this flag; I came up with<br>
> "unconstrainable", but that's a lot of letters and perhaps a bit<br>
> over-specific. What I propose now is "generated".<br>
><br>
> So... what do people think?<br>
><br>
> Thanks,<br>
><br>
> Markus<br>
><br>
><br>
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