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Re: Attributes vs. Elements for Code values

From: Jack Lindsey <Jack@Ottawa.com>
Date: Wed, 16 Apr 2003 22:11:55 -0400
Message-ID: <001e01c30486$b8a42600$dfa27018@slnt.phub.net.cable.rogers.com>
To: <xmlschema-dev@w3.org>, "Dan Vint" <dvint@mindspring.com>

Our general approach is to avoid enumeration within the schema because we typically have way more than a handful of values, often 30 or so, even a couple of thousand for car make and model.  So we wanted to keep code value maintenance independent from schema maintenance since we anticipate issuing code table updates more frequently than schema updates. 

Cheers jack

----- Original Message ----- 
From: "Dan Vint" <dvint@mindspring.com>
To: <xmlschema-dev@w3.org>
Sent: Wednesday, April 16, 2003 9:33 PM
Subject: Re: Attributes vs. Elements for Code values

: My organization has 2 schemas one with each approach. The issue is somewhat 
: of a wash until you consider if you are providing an enumerated list of 
: values. We have found it to be more flexible to have this as element 
: content than as attribute content.
: Originally coming from SGML, I would have pushed the attribute route 
: because a DTD allowed some validation and control of a defined list where 
: element content didn't. Schemas change that and allowed both the manage 
: this issue, now it seems to be how you might want to extend a list of 
: values that settle the discussion.
: At 09:09 PM 4/16/2003 -0400, Jack Lindsey wrote:
: >I want to use XML attributes to hold terse code values (e.g. "CA-BC", 
: >"312120", "23") that are replaced by text in the language of your choice 
: >from lookup tables in XML files (e.g. 
: >"Colombie-Britannique",  "Breweries", "Cul-de-sac") when the XML data is 
: >rendered on a web page.  However, some of my colleagues suffer from 
: >generalized attribute phobia and want to do everything with XML 
: >elements.  I don't see the danger.  Here are my pros and cons.  What do 
: >you think?
: >
: >
: >PRO
: >1. Attributes mean much more compact XML data
: >2. Processing attributes is much more efficient in XSLT and DOM
: >3. Everybody does codes this way
: >
: >CON
: >1. Other people's schemas can't just reuse your codes without also using 
: >the surrounding element, unless you declare your code attributes globally? 
: >Is that right?
: >2. If an element can have multiple values of a code (like Disability in 
: >Being in the example below), you have to create an element for it anyway 
: >so it can occur multiply, and that is the worst option, performance-wise 
: >(according to Scott Bonneau, XML Design handbook, p. 43)
: >3. You don't get that nice XML schema diagrammatic documentation for your 
: >attributes in XML Spy.
: >
: >
: >Sample Data:
: >
: ><Being beingSerialNumber="0002345" genderID="3" speciesID="42">
: >   <BeingBirthDate>1980-04-13</BeingBirthDate>
: >   <Disability disabilityID="17"/>
: >   <Disability disabilityID="24"/>
: >   <MedicalConditionNarrative medicalConditionID="23">Not responding to
: >treatment.</MedicalConditionNarrative>
: >   <MedicalConditionNarrative medicalConditionID="16">Clearing up
: >nicely.</MedicalConditionNarrative>
: ></Being>
: >
: >Cheers Jack
Received on Wednesday, 16 April 2003 22:16:42 UTC

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