Re: varchar vs varchar(n)

thanks!

On Sun, Nov 12, 2017 at 2:34 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> john snow <ofbizfanster(at)gmail(dot)com> writes:
> > do postgresql developers just use varchar instead of specifying a limit n
> > when dealing with string types? if so, are there any gotcha's i should be
> > aware of?
>
> Generally speaking, I would only use varchar(n) when there is a clear
> reason traceable to application requirements why there has to be a
> limit, and why the limit should be n and not some other number.
> Otherwise you're just creating issues for yourself. The habit of
> inventing arbitrary limits on text column width is just a hangover
> from punched-card days.
>
> Actually, Postgres people tend to use "text" rather than unconstrained
> "varchar". In principle those two types behave equivalently; but the
> system has to jump through some extra hoops to work with varchar, and
> every so often you'll run into a case where "varchar" is not optimized
> as well as "text".
>
> regards, tom lane
>