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XML Schema is designed on the basis that you can validate sequentially,
without backtracking. The means you must be able to decide whether the <deg>
value is valid before you've seen the <min> or <sec> value. Therefore, I
think this rule cannot be expressed in XML Schema.
Michael Kay
> -----Original Message-----
> From: Dan White [mailto:ygor@comcast.net]
> Sent: 28 July 2004 21:03
> To: Alex Milowski
> Cc: xml-dev@lists.xml.org
> Subject: Re: [xml-dev] Another Schema Question
>
>
> I need to be able to validate this:
>
> <Latitude>
> <deg>90</deg>
> <min>0</min>
> <sec>00.000</min>
> <dir>N</dir>
> </Latitude>
>
> The value of "degrees" can be 90 only if "minutes" and
> "seconds" are both
> zero. A degee value of 90 with non-zero minutes or seconds
> is invalid.
>
> That's the main problem. I have to allow for someone referencing the
> North/South Pole or , in the case of Longitude, the
> International DateLine
> (180 degrees longitude)
>
> Both present the same problem.
>
> On Wed, 28 Jul 2004, Alex Milowski wrote:
>
> > XMLSpy is clearly wrong in this case.
> >
> > You could try only have one sequence (i.e. get rid of the
> choice) and
> > use
> > defaults for 'min' and 'sec':
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";>
> > <xs:element name="lat" type="LatitudeType"/>
> > <xs:complexType name="LatitudeType">
> > <xs:sequence>
> > <xs:element name="deg">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="90"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:element>
> > <xs:element name="min" default="0">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="60"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:element>
> > <xs:element name="sec" default="0">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="60"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:element>
> > <xs:element name="dir">
> > <xs:simpleType>
> > <xs:restriction base="xs:string">
> > <xs:enumeration value="N"/>
> > <xs:enumeration value="n"/>
> > <xs:enumeration value="S"/>
> > <xs:enumeration value="s"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:element>
> > </xs:sequence>
> > </xs:complexType>
> > </xs:schema>
> >
> > The problem with this (or using fixed) is that the element
> still has to
> > appear:
> >
> > <lat xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
> > xsi:noNamespaceSchemaLocation="lat.xsd">
> > <deg>50</deg>
> > <min/><sec/>
> > <dir>N</dir>
> > </lat>
> >
> > This is one case where attributes have the advantage. You
> can have the
> > instance:
> >
> > <lat deg="50" dir="N"/>
> >
> > and have the schema processor default the 'min' and 'sec'
> attributes to
> > zero (and
> > so your application can always assume they are there). Here's that
> > schema:
> >
> > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";>
> > <xs:element name="lat" type="LatitudeType"/>
> > <xs:complexType name="LatitudeType">
> > <xs:attribute name="deg">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="90"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:attribute>
> > <xs:attribute name="min" default="0">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="60"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:attribute>
> > <xs:attribute name="sec" default="0">
> > <xs:simpleType>
> > <xs:restriction base="xs:decimal">
> > <xs:minInclusive value="0"/>
> > <xs:maxExclusive value="60"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:attribute>
> > <xs:attribute name="dir">
> > <xs:simpleType>
> > <xs:restriction base="xs:string">
> > <xs:enumeration value="N"/>
> > <xs:enumeration value="n"/>
> > <xs:enumeration value="S"/>
> > <xs:enumeration value="s"/>
> > </xs:restriction>
> > </xs:simpleType>
> > </xs:attribute>
> > </xs:complexType>
> > </xs:schema>
> >
> >
> >
> > Alex Milowski FAX: (707) 598-7649
> > alex@milowski.com
> >
> > "The excellence of grammar as a guide is proportional to
> the paucity of
> > the
> > inflexions, i.e. to the degree of analysis effected by the language
> > considered."
> >
> > Bertrand Russell in a footnote of Principles of Mathematics
> >
> >
> >
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>
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