"generated" as column/param flag

[Joshua Fraustro]

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’.

The only things I could offer as alternatives, in order of quality, I think are:

“computed”
“derived”
“dynamic”

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.

If it’s about the data, the above might be a hair better. But if it’s simply about whether a user can filter​ on the data, might I suggest just, filterable​ ?

From: registry <registry-bounces at ivoa.net> on behalf of Patrick Dowler via registry <registry at ivoa.net>
Date: Wednesday, April 15, 2026 at 9:59 AM
To: dal at ivoa.net <dal at ivoa.net>; registry at ivoa.net <registry at ivoa.net>
Subject: Re: "generated" as column/param flag

External Email - Use Caution

+1 for generated
--
Patrick Dowler
Canadian Astronomy Data Centre
Victoria, BC, Canada

On Wed, 15 Apr 2026 at 06:40, Markus Demleitner via dal <dal at ivoa.net> wrote:
>
> Dear DAL, dear Registry,
>
> In the TAP issue https://urldefense.com/v3/__https://github.com/ivoa-std/TAP/issues/11__;!!CrWY41Z8OgsX0i-WU-0LuAcUu2o!0NPj16JCZWyKwR44NKUjCNd3yTmk4xa5nGeafwhnWMJ2zaY9IP9iT2W05dVfpQOL6AlqgKUYQIyYVKUBsg$ , Pat and I
> found that it would be really desirable to align the flags (indexed,
> std, principal, primary, nullable) we have for columns (in
> TAP_SCHEMA.columns) and TableParam-s (in VODataService tablesets).
>
> The immediate occasion was that we should have a way to signal "What
> you see on output in here is not necessarily what is in the database"
> or, in effect, "you cannot write constraints against this column".
> The classic use case from my end is that for most access_urls, DaCHS
> stores a relative path and produces an appropriate URL based on where
> it thinks it is running.  But there are many other use cases as well.
>
> To address that, I am proposing a flag in the sense of TAP issue #11
> for VODataService given it is nearing PR/RFC:
> <https://urldefense.com/v3/__https://github.com/ivoa-std/VODataService/pull/17__;!!CrWY41Z8OgsX0i-WU-0LuAcUu2o!0NPj16JCZWyKwR44NKUjCNd3yTmk4xa5nGeafwhnWMJ2zaY9IP9iT2W05dVfpQOL6AlqgKUYQIxwclF2vw$ >.
>
> We were thinking about a good literal for this flag; I came up with
> "unconstrainable", but that's a lot of letters and perhaps a bit
> over-specific.  What I propose now is "generated".
>
> So... what do people think?
>
> Thanks,
>
>           Markus
>
>
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