Re: Document oriented experience reports anyone?
Hello All, I work for fairly large company in the Knowledge Management department. Basically, we manage all of the engineering documents (with very few exceptions). We started out using DTDs, but I am planning to implement XML Schema in the next year or so. Here is the logic behind this decision: 1) Support for namespaces Our documents have lots of equations, but the original creator of the DTD decided not to use MathML because there was no tool support (we are using XMetal 3.1, but have upgraded to 4.5/4.6 and have purchased Design Science Mathflow). We are now finding that MathML is essential. I know you can use the MathML DTD and included in our existing one, but I find it easier just to import it in a schema. And our DTD contains two elements with that have the same name as elements in the MathML DTD. Some tools complain about this (I can't recall if XMetal does, but I know XMLSpy points it out). 2) Restrict what text content appears inside elements All of our documents have dates in them, usually issue date, revision date, and approval date. These elements all contain year, month, and day elements in their content model. In the DTD system, people can (and do) put anything in these elements (for example "Mar" in the month element instead of "03", which is the standard here). We do have guidelines and the people in my department tend to follow them, but we plan to start letting the end user create their own XML documents. I know from experience that they don't always 'play by the rules'. Using schema validation is a good way to enforce content consistency. Those are my two biggest reasons for using schemas. However, there is one big drawback: no entity support. We have a lot of standard text in documents such as legal statements, addresses, and other text. Legal statement can (and probably should) be standardized at the stylesheet level, but things like an address that may or may not appear in the document can't be. I am unsure yet how I will tackle this problem. In summation, schema can be very useful in publishing, but the lack of entity support is a huge drawback. I guess I should copy and paste this in word and send it to the W3C! Nadia Swaby Rick Jelliffe <ricko@a... To: XML Developers List <xml-dev@l...> m.au> cc: Subject: Re: Document oriented experience reports anyone? 2005-06-08 04:25 Does "I know of almost no large uses of XSD for documents" count? A non-experience report? The crowd I come in contact with (mostly the kinds of users who used SGML before: military, legal, pharmeceutical) are very conservative as far as editing environments: if they are using FrameMaker they are stuck with DTDs, if they are using text editors or markup editors (like Topologi's) they usually want to have character entity references and so keep with DTDs, if they are using Word->XML conversion they hard code some schema (usually a DTD) into the converter code, and so on. Furthermore, document-oriented systems very often have large files that tree-based tools (such as those that use XML Schemas) often won't open successfully. Furthermore, the large companies tend to have evolving systems and evolving schemas, so they don't get much value from switching from one grammar to another. And, where they do want more modeling power, RELAX NG is more powerful than XSD. (And if the site has no tools for applying default values from a XSD, it again loses out to DTDs and is on par with RELAX NG.) The trouble with moving to XML Schemas is that it may involve substantial re-tooling. For example, the recent release of Epic editor supports XML Schemas: users who have a small number of document types expressed in XML Schemas but many expressed with DTDs have to figure out whether it is more practical to convert the XML Schemas to DTDs or upgrade their editing/production environments. (Or just to avoid XSD.) Finally, publishing data is rife with co-occurrence constraints: serious publishers may be more interested at implement Schematron. So, realistically, I only expect to see widespread XML Schemas adoption for documents piggybacking on the release of new industry standards: S-1000D and DITA for examplein the short-term. These don't come out very often, compared to data-oriented standards, and the promulgators of these may decide to put out DTD or RELAX NG versions just to aid adoption. In the long-term, retooling and upgrades will make XSD-using tools more available, and it will make XSD much more viable, though still not particuarly interesting. Cheers Rick Jelliffe ----------------------------------------------------------------- The xml-dev list is sponsored by XML.org <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this list use the subscription manager: <http://www.oasis-open.org/mlmanage/index.php>
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