RE: Schema keys and XSLT implementation

> I have a XLST that reads XML from zap2it.com (via SOAP) and I 
> declare several keys.  I was reading 
> their schema and it also has similar 'xsd:key', 'xsd:keyref', 
> and 'xsd:unique' elements.  My question 
> is -- is my xsl:key statements redundant?  And can I just 
> phrase a "key()" search function based on 
> the schema, or is the schema for documentation only?

The keys defined in the schema are there for validation purposes, while the
keys defined in the stylesheet declare indexes for efficient access. They
have no relationship to each other.

A schema-aware XSLT processor could make use of the existence of keys in the
schema to create implicit indexes for efficient access in your stylesheet,
but the only schema-aware XSLT processor currently in existence (Saxon-SA)
doesn't (yet) do that.

An XSLT 1.0 processor such as libxslt is very unlikely to make any use of
schema information, though it could do so in theory.

Michael Kay
http://www.saxonica.com/


> 
> I have read "XSL Transformations" 
> (http://www.w3.org/TR/xslt), but they dont mention a schema 
> connection.
> 
> BTW, this is a general XSLT language question ... but if it 
> depends on implementation I am using 
> xmlsoft.org (aka. Gnome) libxslt v1.1.12.
> 
> 
> These are my xsl:key statements:
>    <xsl:key name="station_keyref_schedule" 
> match="./ns1:schedules/ns1:schedule" use="@station" /> 
>    <xsl:key name="program_key" 
> match="./ns1:programs/ns1:program" use="@id" /> 
>    <xsl:key name="genre_keyref" 
> match="./ns1:genres/ns1:programGenre" use="@program" /> 
>    <xsl:key name="crew_keyref" 
> match="./ns1:productionCrew/ns1:crew" use="@program" /> 
> 
> 
> And the relevant schema portion 
> (http://docs.tms.tribune.com/tech/xml/schemas/tmsxtvd.xsd):
> 
> <xsd:key name="station_key"> 
>    <xsd:selector xpath="./stations/station"/> 
>    <xsd:field xpath="@id"/> 
> </xsd:key> 
> <xsd:keyref name="station_keyref_schedule" refer="tms:station_key"> 
>    <xsd:selector xpath="./schedules/schedule"/> 
>    <xsd:field xpath="@station"/> 
> </xsd:keyref> 
> <xsd:unique name="program_key"> 
>    <xsd:selector xpath="./programs/program"/> 
>    <xsd:field xpath="@id"/> 
> </xsd:unique> 
> <xsd:keyref name="crew_keyref" refer="tms:program_key"> 
>    <xsd:selector xpath="./productionCrew/crew"/> 
>    <xsd:field xpath="@program"/> 
> </xsd:keyref> 
> <xsd:keyref name="genre_keyref" refer="tms:program_key"> 
>    <xsd:selector xpath="./genres/programGenre"/> 
>    <xsd:field xpath="@program"/> 
> </xsd:keyref> 
> 
> 
> The XML outline is:
> 
> <xtvd from='2005-07-20T11:30:00Z' to='2005-07-21T00:00:00Z' 
> schemaVersion='1.3' xmlns='urn:
> TMSWebServices' 
> xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' 
> xsi:schemaLocation='urn:
> TMSWebServices 
> http://docs.tms.tribune.com/tech/xml/schemas/tmsxtvd.xsd'>
> ...
> <stations> 
>   <station id="10398"> 
>     
> <callSign>KDAF</callSign><name>KDAF</name><fccChannelNumber>33
</fccChannelNumber><affiliate>WB 
> Affiliate</affiliate> 
>   </station> 
>   <station id="10402"> 
>     
> <callSign>KDFW</callSign><name>KDFW</name><fccChannelNumber>4<
/fccChannelNumber><affiliate>Fox 
> Affiliate</affiliate> 
>   </station> 
> </stations> 
> <schedules><schedule program="SH6948700000" station="10398" 
> time="2005-07-20T11:30:00Z" 
> duration="PT00H30M"/> 
> ... 
> <schedule program="SH1966900000" station="10402" 
> time="2005-07-20T11:00:00Z" duration="PT01H00M"/> 
> ... 
> </schedules> 
> <programs> 
> ... 
> <program id="EP0000510180"><title>A Different 
> World</title><subtitle>When One Door Closes ...
> <subtitle><description>A Japanese corporation woos Dwayne for 
> his software; Whitley is pregnant; 
> guests Diahann Carroll, Patti 
> LaBelle.</description><showType>Series</showType><series>SH000051</
> series><syndicatedEpisodeNumber>9216B</syndicatedEpisodeNumber
> ><originalAirDate>1993-05-08</
> originalAirDate></program> 
> ... 
> <program id="SH1966900000"><title>Good Day at 
> 6:00AM</title><description>Henderson, Ryan.</
> description><showType>Series</showType><series>SH196690</serie
s><originalAirDate>2001-06-21</
> originalAirDate></program> 
> ... 
> </programs> 
> <productionCrew><crew 
> program="EP0000510180"><member><role>Actor</role><givenname>Jasmine</
> givenname><surname>Guy</surname></member> 
> ... 
> </crew> 
> ... 
> </productionCrew> 
> <genres><programGenre 
> program="EP0000510180"><genre><class>Sitcom</class><relevance>
0</relevance></
> genre></programGenre> 
> ... 
> </genres> 
> </xtvd>
> 
> 
> Thx for any pointers ....
> -- 
> Rodman