Cart
|
[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: RE: The real world doesn't have an "other xyz", neithersho
 I believe this book is in order ; http://www.everythingismiscellaneous.com/ And as a former librarian; categorisation is futile, even if often useful. Cheers, Alex On Wed, Feb 12, 2014 at 2:01 PM, Rick Jelliffe <rjelliffe@allette.com.au> wrote: > I agree with Bruce that "other" sometimes indicates a failure or limitation > of analysis. > But some lists cannot be enumerated; sometimes the world changes; sometimes > categories change; some things are one way in one part of the world but a > different way elsewhere; some things requested should not be disclosed. > Gender and post addresses are two things that people expect are quite fixed, > but turn out not to be. > And then some "other" facilities in xml are dictated by the unlayered nature > of xsd and dtds: conservative and slow development and distribution > practises that are appropriate for base vocabulary elements may not be > appropriate for code lists maintained on other timelines. If your schema > cannot track the codelists used, it needs a temporary other for interim > parking. > > Rick > > On 11/02/2014 5:00 AM, "Cox, Bruce" <Bruce.Cox@uspto.gov> wrote: >> >> In my work, I've often preached that a Schema/DTD should model the >> business process. When someone wants an "other" element or attribute value, >> it's almost always because the business process is ill defined, sometimes >> inadvertently, sometimes deliberately. So long as no one expects very much >> from any machine processing of the value of an "other" element or attribute >> (other than recording the value, for example). Yes, it's useless, but also >> probably harmless. >> >> Still, it's a laudable goal, Roger. >> >> Bruce B Cox >> OCIO/AED/Software Architecture and Engineering Division >> 571-272-9004 >> >> >> -----Original Message----- >> From: Costello, Roger L. [mailto:costello@mitre.org] >> Sent: 2014 February 9, Sunday 09:27 >> To: xml-dev@lists.xml.org >> Subject: The real world doesn't have an "other xyz", neither should your >> XML >> >> Hi Folks, >> >> I see many XML instances (and corresponding XML Schemas) with an "other" >> catchall element. >> >> I wish to convince you that an "other" catchall element is contrary to >> one's objectives and should be avoided. >> >> First, a quote from the book, "Principles of Program Design" (Jackson >> Design Methodology): >> >> The structure of a program must be >> based on the structures of all the data >> it processes. >> >> A corollary to that is: >> >> Data should model the real world. >> >> So there is this deep connection: >> >> real world --> data model --> program structure >> >> In the real world there is no "other" component: When was the last time >> you drove an "other car" or purchased an "other vegetable"? >> >> So it is wrong to create a data model for a nonexistent real world entity. >> Likewise it is wrong to write a program component for "other" data. >> >> Let's take an example. Suppose we use XML Schema to model the countries of >> the world: >> >> <xs:element name="Country"> >> <xs:complexType> >> <xs:choice> >> <xs:element name="Afghanistan" type="countryType" /> >> <xs:element name="Albania" type="countryType" /> >> ... >> <xs:element name="Zimbabwe" type="countryType" /> >> <xs:element name="Other" type="countryType" /> >> </xs:choice> >> </xs:complexType> >> </xs:element> >> >> Since the countries of the world are ever-changing, we include an "Other" >> element in anticipation of some future, unforeseen country. >> >> It is easy to imagine assigning a program component to Iceland: >> >> <Country> >> <Iceland>...</Iceland> >> </Document> >> >> But what is a program component to do when it encounters the "Other" >> country: >> >> <Country> >> <Other>...</Other> >> </Document> >> >> There is no "Other" country and so any operation that we might assign to >> the data would be nonsensical. >> >> Stated another way: >> >> "Other" data is not machine-processable. The reason >> for using XML is that to enable machine-processing. >> But by incorporating non-machine-processable >> "other" data one's own objectives are defeated. >> >> "Okay, suppose that I avoid using an <Other> element and, say, a new >> country emerges; what should I do?" >> >> Answer: the real world has changed (there is a new country). Your data >> model must be updated to reflect the real world. So update your XML Schema >> and in your program add a component for the new country. >> >> Comments welcome. >> >> /Roger -- Project Wrangler, SOA, Info Alchemist, UX, RESTafarian, Topic Maps http://shelter.nu/blog | google.com/+AlexanderJohannesen http://xsiteable.org | http://www.linkedin.com/in/shelterit 
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] |
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! 
Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|
|||||||||
