Hello.
Some example:
compile and install contrib/tsearch module
and now:
wow=# create table foo (bar txtidx);
CREATE
wow=# \d foo
Table "foo"
Column | Type | Modifiers
--------+--------+-----------
bar | txtidx | not null
Why field 'bar' has modifier 'not null'?
--
Teodor Sigaev
teodor(at)stack(dot)net