As I said in my post, this is a general principle for me. Nominal data should have a data type of some sort of character. You will never run into unexpected problems down the line.
On Thu, May 14, 2009 at 11:04 AM, Pete Wilson <pete...@yahoo.com> wrote: > > > I'm new to MySQL so can't answer the OP's question, but: > > MAC addresses do not by design contain letters. Native MAC addresses are > 48-bit (6-byte) integers: > > http://standards.ieee.org/getieee802/download/802-2001.pdf > > The confusion arises because a MAC address is usually /represented/ as > hexadecimal, and that might contain letters, but MAC addresses natively > are pure 6-byte integers. > > So the issue is whether you want to index by a 48-bit number or a > 12-character ascii string. For efficiency's sake, I'm guessing you'd choose > the former. > > I'll be interested in the answer, though, from someone with experience. > > -- Pete Wilson > http://www.pwilson.net/ > > > --- On Thu, 5/14/09, Jim Lyons <jlyons4...@gmail.com> wrote: > > > From: Jim Lyons <jlyons4...@gmail.com> > > Subject: Re: MAC address as primary key - BIGINT or CHAR(12) > > To: "Ilia KATZ" <ik...@dane-elec.co.il> > > Cc: mysql@lists.mysql.com > > Date: Thursday, May 14, 2009, 11:38 AM > > Definitely CHAR (or VARCHAR). > > > > If the format of a MAC address changes at all, you could be > > in real > > trouble. Also, if a MAC address can have a leading 0 > > (I don't know anything > > about MAC addresses), then storing it as some sort of > > number could lose > > that. > > > > This is a general rule for me. A field might only > > contain numbers (at one > > particular point in time) but if those numbers are > > really nominal data (in > > which the size or order does not matter) then they should > > be CHAR or VARCHAR > > fields anyway. > > > > On Thu, May 14, 2009 at 8:26 AM, Ilia KATZ <ik...@dane-elec.co.il> > > wrote: > > > > > Hi. > > > Currently I have a table: > > > 1. MAC address defined as BIGINT > > > 2. MAC address set as primary key > > > > > > Should I consider changing it to CHAR(12)? > > > > > > Replies will be appreciated. > > > Ilia > > > > > > > > > > > > > > > > > > -- > > Jim Lyons > > Web developer / Database administrator > > http://www.weblyons.com > > > > > > -- Jim Lyons Web developer / Database administrator http://www.weblyons.com
