Re: Clue to define a field data type

--As of August 10, 2014 1:40:11 PM -0500, JORGE MALDONADO is alleged to
have said:

> I have a table which will contain a set of pre-defined records defined by
> the government of my country. The fields are ID and DESCRIPTION. The ID
> field is composed of 3 characters that are always numbers. This means
> that I can set such a field as a char(3), varchar(3), smallint or
> integer, for example, and all of them will provide the correct
> functionallity. My question is, why should I define such a field as a
> character based type or a numeric based type? What is the best choice if
> this field will always be a 3-digit number?

--As for the rest, it is mine.

My opinion: Unless you are doing arithmetic, it's better to stick to a char
field of some type. In this case especially, the fact that the ID is only
numeric is incidental - at some future point someone could decide they need
more than 1000 ID fields, and start using letters. (They could also decide
to lengthen it instead.)

The only reason to store them as numbers is that it would be slightly more
space-efficient, but it would be *very* minor. My recommendation is to use
varchar(3).

Daniel T. Staal

---------------------------------------------------------------
This email copyright the author. Unless otherwise noted, you
are expressly allowed to retransmit, quote, or otherwise use
the contents for non-commercial purposes. This copyright will
expire 5 years after the author's death, or in 30 years,
whichever is longer, unless such a period is in excess of
local copyright law.
---------------------------------------------------------------