NULL-valued TAP_SCHEMA boolean columns?

[Mark Taylor]

Hi TAPistas,

Another TAP validation quibble.

The TAP_SCHEMA.columns table (TAP section 2.6.3) contains three required
integer columns (std, principal, indexed) annotated thus:

   "1 means true, 0 means false"

Question: is it legal to have NULL values in these columns?
The implication of the text seems to be that this is not permitted
(since other column descriptions say things like "if known" where
NULL is permitted), but it's not explicit.

Thanks

Mark

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/