NAME or ID

[Roy Williams]

Clive

The NAME and ID fields are admittedly close in meaning. Here is the
difference.

The NAME is about readability, and should be used where humans see are to
read. The ID is about uniqueness, so that computers can distinguish one
column from another.

If only NAMES are present, then these can be used in place of ID -- but only
if uniqueness checking is done. If only IDs are present, these may be used
as NAMES, but they may be meaningless (eg ID="F784673638")

Roy

--------
Caltech Center for Advanced Computing Research
roy at cacr.caltech.edu
626 395 3670

----- Original Message -----
From: "Clive Page" <cgp at star.le.ac.uk>
To: <votable at ivoa.net>
Cc: "Clive Davenhall" <C.Davenhall at roe.ac.uk>
Sent: Thursday, June 12, 2003 7:40 AM
Subject: NAME or ID


> Dear VOTable expert:
>
> I'm a bit confused about the relative importance of the
> NAME= and ID= attributes of the <FIELD element.
>
> Section 4.3 of the VOTable document implies that ID is fundamental, though
> it stops short of saying that it is required.  It says that if NAME is not
> present it defaults to ID, which strongly implies that NAME is optional.
>
> The sample VOTable shown in section 8 has both ID and NAME for each FIELD,
> on the other hand the example in section 1.1 shows just NAME and not ID.
> Is this legal?  There's another example in section 6.1.1 has an ID
> and not a NAME, which seems more likely to be ok.
>
> I came across this problem when using the VOPLOT utility from the Indian
> VO, which seems to require NAME but does not care about ID.  With the
> defining document apparently somewhat ambivalent about this, such
> discrepancies are to be expected.  Would a VOTable guru like to comment?
>
>
> --
> Clive Page,
> Dept of Physics & Astronomy,
> University of Leicester,    Tel +44 116 252 3551
> Leicester, LE1 7RH,  U.K.   Fax +44 116 252 3311
>