optional column "datalink_url" cannot be found

[Laubeee]

Hi, it seems the optional column datalink_url as documented here does not work. When I try to use it:

<table id="epn_core" onDisk="True" adql="True">
  <mixin spatial_frame_type="none" optional_columns="datalink_url time_scale thumbnail_url access_estsize" >//epntap2#table-2_0</mixin>
</table>

it errors with 'datalink_url' could not be located in table optional_columns

As a workaround I defined the column myself with:

<column name="datalink_url" type="text" ucd="meta.ref.url;meta.datalink" description="Link to folder with observation fits files" />

solutions are to either update the documentation or the optional columns

Cheers

[Erard]

That's right. You'll find (old) examples of datalink in EPN-TAP service here
https://github.com/epn-vespa/DaCHS-for-VESPA/blob/master/q.rd_examples/spicam/q.rd_spicam
https://github.com/epn-vespa/DaCHS-for-VESPA/blob/master/q.rd_examples/hst/HST_q.rd

[BaptisteCecconi]

Hello @Laubeee, indeed the datalink_url is not yet implemented in the mixin The column must be implemented manually, at this point.

However, the use of this optional column should be described in more details, since it is not in the Datalink standard.

[Laubeee]

Small detail: is there anything that makes the ADQL query form result display the column as an actual URL, like it does with access_url?

[Erard]

You mean in DaCHS? I think not. It actually links to a page built on the fly. You can experiment with TOPCAT, which has internal support for datalink, or with the VESPA portal.