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RE: representing fixed point decimal types

From: Cole, Russ E <Russ.Cole@unisys.com>
Date: Wed, 1 May 2002 15:02:02 -0500
Message-ID: <ABC8C2B0E4A1CA47B79A03B1E939BFEA01176A01@USMV-EXCH3.na.uis.unisys.com>
To: Jeni Tennison <jeni@jenitennison.com>
Cc: xmlschema-dev@w3.org
Thanks for the information, Jeni.

Does anyone know the rationale for the design of totalDigits/fractionDigits?
What problem do they solve without having to use some sort of 'restriction'?
I had assumed (probably because of the incorrect example) that the decimal
type would have been designed so that fixed point numbers could have been
defined simply.  I'm just curious; it's not important.

Russ Cole

-----Original Message-----
From: Jeni Tennison [mailto:jeni@jenitennison.com]
Sent: Wednesday, May 01, 2002 11:50 AM
To: Cole, Russ E
Cc: xmlschema-dev@w3.org
Subject: Re: representing fixed point decimal types


Hi Russ,

> Am I right that there are no fixed point types in xml schema? The
> closest thing I can find to precision/scale is
> totalDigits/fractionDigits. So, I find myself using
> minInclusive/maxInclusive. For example, for precision 8 scale 2:
>
> <xs:simpleType>
>               <xs:restriction base='xs:decimal'>
>                <xs:totalDigits value='8'/>
>                <xs:fractionDigits value='2'/>
>                <xs:minInclusive value='-999999.99'/>
>                <xs:maxInclusive value='999999.99'/>
>               </xs:restriction>
> </xs:simpleType>

Another method that you could use is to use a pattern to say that you
want exactly two decimal digits:

  <xs:simpleType>
    <xs:restriction base="xs:decimal">
      <xs:totalDigits value="8" />
      <xs:fractionDigits value="2" />
      <xs:pattern value="-?\d{1,6}\.\d{2}" />
    </xs:restriction>
  </xs:simpleType>

The pattern allows an optional minus sign, followed by between 1 and 6
digits, followed by a decimal point, followed by two digits.
  
> Also, the example in the xml schema standard seems wrong to me
> because it says using totalDigits 8 and fractionDigits 2 constrains
> the value to be less than 1 million whereas it only constrains the
> value to be less than 100 million.

I think that's already been noted. See
http://www.w3.org/2001/05/xmlschema-rec-comments#pfiTotalDigits

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/
Received on Wednesday, 1 May 2002 16:02:19 UTC

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