[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Re: Are the data users happy? Why not?
K. Ari Krupnikov scripsit: > John, the question is not "can I validate some string against *some > criterion* because I have a tool that will?". The question is "can I > validate some string wrt the use I intend to make of it". No, it's "Can I cheaply and easily reduce the error rate in entered data"? Full validation is beyond my powers, since I can't make my computer send snail mail, still less process the replies. > But how do you know it's *their* post code? Something tells me you are > interested in the singleton set of *the user's* post code, not the > larger set of *valid* post codes. Is a valid, but irrelevant, post > code better for you than no post code at all or a bogus post code? > 20502 is a valid US ZIP code. Do you want to send mail there that is > addressed to me? If you enter that, it's your problem. But if you mean to type 10003 and type 1003, I will not accept that (given country=US). > Whose money you take is up to you. But after you take their money, you > want to know where they are, don't you (although I'm not sure why)? Partly because I get a cheaper rate from a credit card processor if the address I supply matches the one associated with the card. In addition, users don't get access without a signed contract, and I need somewhere to tell Sales to send it. > Presumably, you give your users a drop-down list and not a text field > to reduce data-entry errors. As the list of enumerations grows longer, > it becomes a greater potential source of errors than an unconstrained > string because users can't be bothered to read through its entire > length. A valid point. If more people knew their ISO 3166 country code, I would allow them to type that and validate it on the fly. > Validation, wither regexp- or set-based, only catches so many errors, > while giving you the illusion that your data are somehow > correct. No, while giving me the assurance that my data is not incorrect in easily checkable ways. It does not refer to a non-existent country (though it could refer to the wrong country); it does not refer to an impossible zip code (though it could refer to an unused or incorrect one). -- John Cowan http://www.ccil.org/~cowan jcowan@r... Please leave your values | Check your assumptions. In fact, at the front desk. | check your assumptions at the door. --sign in Paris hotel | --Cordelia Vorkosigan
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