I think the ODBC spec limits varchar to 255 bytes.
Some ODBC drivers enforce that limit.
Tom Lane wrote:
> "Jeffrey A. Rhines" <jrhines@email.com> writes:
> >> Uh ... what's wrong with varchar(n) ?
> >
> > I've wondered that myself, actually. What are the benefits and
> > drawbacks to going with one over the other, besides the obvious 255-char
> > field length limit for varchar?
>
> AFAIK there has *never* been a 255-char limit on char or varchar in
> pgsql ... you must be thinking of Some Other DBMS.
>
> [snip]
> regards, tom lane