From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | john snow <ofbizfanster(at)gmail(dot)com> |
Cc: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: varchar vs varchar(n) |
Date: | 2017-11-12 19:34:52 |
Message-ID: | 21800.1510515292@sss.pgh.pa.us |
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Lists: | pgsql-novice |
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
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