The other idea I had aside from mnemonic (that was yours) was to use beefier numbers. I started listing them from 1. I am thinking of 3 digits maybe.
Stuart --- Rhino <[EMAIL PROTECTED]> wrote: > > ----- Original Message ----- > From: "Stuart Felenstein" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, August 25, 2004 3:36 PM > Subject: Could this be dangerous :Values and Labels > > > > Or maybe just bad practice. Thought before I go > any > > further I'll ask. > > > > I have a few static tables that list out "items" > and > > the primary key is an "assigned" ID. Meaning I > did > > not set auto-increment. As I add items I will add > the > > associated ID number. > > > > Now to the transactional tables. While the label > has > > the item listed in the form, it gets inserted into > the > > table with the ID number. To illustrate: > > > > Static_Table > > ID Value > > 1 United > > 2 Jet Blue > > 3 Southwest > > 4 American > > > > Dynamic_Table > > MemberID Airline_Pref > > 200 1 > > 201 4 > > 202 3 > > 203 4 > > 204 1 > > > > Pros cons dangers advantages comments ? > > > I *think* you're asking if it is okay to use codes > instead of real values in > databases, such as '1' for 'United'. That is more > than okay, it is very > widely done. > > The pros are pretty obvious: > - codes are usually much shorter than the real > values, which results in > space savings for data storage > > The cons are a little less obvious: > - unless you memorize the codes (which you *will* > tend to do over time, as > long as there aren't too many of them), you will > have to do lookups to > determine what real value corresponds to a given > code. That often translates > into extra joins in your programs and queries. This > should not be a big deal > though since joins usually perform pretty well in > most cases. > > I'd like to offer one comment. If I were making up > the codes, I'd try to > choose codes that were mnemonic, such as 'U' for > 'United' and 'A' for > 'American'. (Or maybe 'UA' and 'AA' since those > abbreviations might be > self-explanatory to many users of your system.) > > Lastly, with regards to Auto-Increment, you should > not feel that all keys > should be Auto-Incremented. I think of > Auto-Increment as a convenience for > generating key values when you don't have any strong > preference for a given > key having a given value. However, I don't think you > should ALWAYS use > Auto-Incremented keys. For example, your airline > lookup table is more > meaningful if you use short letter codes for your > airlines than if you use > integers. > > Rhino > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
