> 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...
- Thomas
--
Thomas Lockhart lockhart@alumni.caltech.edu
South Pasadena, California