[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: It is okay for things to break in the future!
Michael Kay <mike@saxonica.com> writes: >> >> This is a really, really common mistake made by inexperienced >> developers - we used to see this all the time in phone number >> formats, for example. Then mobile numbers came along and changed the >> formats. And international phone calls became really common, >> necessitating country codes as a standard part of phone numbers. Etc >> etc etc :) >> > > I have had to invent an imaginary US phone number before now in order > to get past such stupid validation rules. > > A golden rule of validation - never force your users to enter > incorrect data in order to get past your validation rules! On a more sombre note, consider the tradeoff between the benefits of having data that's clean according to some rules and the costs of making data fit those rules. In 1996, when a bomb threat was called in regarding a bomb at the Olympic stadium in Atlanta, the 911 operator spent ten minutes trying to make the 911 system accept the report -- "Centennial Park" was not accepted as the location of interest, because the system was programmed to require a valid street address with street name and number. (I had the same trouble trying to report an apparent car accident in Baltimore's Druid Hill Park once; the dispatcher could not enter the report without a street address, so after explaining the problem I made one up. In the county where I live, a significant number of voter registration records have location information like "white house 3/4 mi southwest of intersection of US 84/285 and NM 399" -- a data validation routine that expects a house number followed by a street name is going to be worse than useless.) -- C. M. Sperberg-McQueen Black Mesa Technologies LLC http://blackmesatech.com
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