Altova Mailing List Archives>Archive Index >xml-dev Archive Home >Recent entries >Thread Prev - [xml-dev] The meaning of the "string" datatype? >Thread Next - Re: [xml-dev] The meaning of the "string" datatype? Re: [xml-dev] The meaning of the "string" datatype?To: "xml-dev@-----.---.---" <-------@-----.---.---> Date: 4/15/2009 1:21:00 PM Costello, Roger L. wrote: > > The content of <Author> can be characters from any language - English, Chinese, Arabic, Italian, Greek, German, Spanish, Russian, etc - plus punctuation symbols plus math symbols. If I did my arithmetic correctly [1], the total number of different characters is: 1,112,000. > Strictly, languages don't have characters, they have writing systems, and writing systems use scripts, and scripts are made from characters. Furthermore, Unicode has Private Use Areas which allow non-standard characters to be represented. XML Schemas String datatype is perhaps better thought of as an anti-datatype rather than a datatype. What it does is signify an absence of a value-space: it is not asserted to be a number, not asserted to be a date, not asserted to be a boolean. This is of course a little topsy turvy. I had a case with an insurance company who received data from the agents which had standard fields but the fields could contain any notation. There was a separate process where people would check the fields and "re-work" them into the standard notations. So the input might have <date>20th May, 2010</date> and after rework it would contain <date>2010-05-20</date> They were surprised to learn that they could not merely say that the incoming data was a string, and then restrict this string to be a date type. (Since xs:date is not a restriction of xs:string.) The original XML Schemas datatype hierarchy was not designed with document refinement in mind (i.e. marking up the document, passing it as text through several different XML stages): the design only makes sense if you assume that the data is living in a DBMS, i.e. where the types are actually primitive storage types for DBMS. Cheers Rick Jelliffe _______________________________________________________________________ XML-DEV is a publicly archived, unmoderated list hosted by OASIS to support XML implementation and development. To minimize spam in the archives, you must subscribe before posting. [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ Or unsubscribe: xml-dev-unsubscribe@l... subscribe: xml-dev-subscribe@l... List archive: http://lists.xml.org/archives/xml-dev/ List Guidelines: http://www.oasis-open.org/maillists/guidelines.php | ||||||
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