> > oh and what is the best datatype to use for a 10 digit phone number?. -snip- > Secondly, for a phone number, ask yourself how you're going to treat it. > Are you going to do a sum() across the numbers? Or maybe multiply them > together? > > If yes, then you should store them as some kind of numeric, int, or as a > float. > > If, however, the numbers are not going to be used for math but for > identification, then it is likely that a text / varchar type would be a > better choice. Don't use int: create table foo (ph int); insert into foo values (5105551212); ERROR: dtoi4: integer out of range Use char(10). Better yet, "properly" normalize phone numbers into area-code (char(3)), prefix (char(3)) and number (char(4)) fields. This way you can error-check your phones against the area-code table, determine approximate geographical areas/time-zones, flag dangerous numbers (very high cost off-shore versions of 900/976 numbers that look like ordinary phone numbers), etc. If you really want to you can even include a prefix table to do the same thing at the exchange level using NANPA data. Even if you don't use a prefix table, updating your table when area-codes split will be easier if the ac and prefix are in their own fields. It may be overkill for your app but for a variety of reasons is a requirement for ours. Cheers, Steve
