Re: [HACKERS] Re: AWL: Re: tm1

Bruce Momjian <maillist@candle.pha.pa.us>

From: Bruce Momjian <maillist@candle.pha.pa.us>
To: Thomas Lockhart <lockhart@alumni.caltech.edu>
Cc: applixware-list@applix.com, Postgres Hackers List <hackers@postgreSQL.org>
Date: 1999-11-12T16:50:06Z
Lists: pgsql-hackers
> > People may have problems with the NULL statements with some versions
> > of PostgreSQL.  I have information about editing the applix macro
> > on that creates the tables my web site:
> >         http://www.radix.net/~cobrien/applix/applix.txt
> 
> Just in case someone cares ;)
> 
> The "NULL" constraint for a column definition is not defined in SQL92,
> and is not necessary and could be dropped from Applix's definition of
> the table. The default behavior of any column defined in SQL is to
> allow NULL values. 
> 
> Postgres does not implement this redundant syntax extension because
> yacc-style parsers such as the one used in Postgres find the use of
> the bare NULL an ambiguous context. Presumably that is why SQL92 does
> not define it.
> 
> However, I see that in a limited context, such as a bare NULL with no
> other qualifiers, yacc can handle its use. I'll add it to Postgres'
> next release...

Yes, we are hearing people use it.  Seems like we could just ignore the
NULL if possible.

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