How to match and merge XML in database? - xslt

Question

I have below mixed documents in one collection.
B3:
<creditRisk>
<characteristic>
<score>
<LID>C230</LID>
<SPID>129587</SPID>
<Sector>Finance and Insurance</Sector>
</score>
<score>
<LID>C177</LID>
<SPID>360720</SPID>
<Sector>Mining and Oil and Gas Extraction</Sector>
</score>
</characteristic>
</creditRisk>
B4:
<creditRisk>
<pit>
<score>
<LID>C230</LID>
<SPID>129587</SPID>
<LTV>1.4689503</LTV>
<LGD>0.5995806998</LGD>
<Logarithm>-0.915243031</Logarithm>
</score>
<score>
<LID>C177</LID>
<SPID>360720</SPID>
<LTV>1.524224737</LTV>
<LGD>0.8989534312</LGD>
<Logarithm>-2.292173791</Logarithm>
</score>
</pit>
</creditRisk>
At the moment to simplify the problem, I need to merge pit/score#B4 when its SPID equals to characteristic/score/SPID#B3 inside MarkLogic. 
Expected Output:
<characteristic>
<score>
<default>
<LID>C230</LID>
<SPID>129587</SPID>
<LTV>1.4689503</LTV>
<LGD>0.5995806998</LGD>
<Logarithm>-0.915243031</Logarithm>
</default>
<LID>C230</LID>
<SPID>129587</SPID>
<Sector>Finance and Insurance</Sector>
</score>
<score>
<default>
<LID>C177</LID>
<SPID>360720</SPID>
<LTV>1.524224737</LTV>
<LGD>0.8989534312</LGD>
<Logarithm>-2.292173791</Logarithm>
</default>
<LID>C177</LID>
<SPID>360720</SPID>
<Sector>Mining and Oil and Gas Extraction</Sector>
</score>
</characteristic>
We are facing issue. My xsl comes out all blank results.
<xsl:template match="characteristic">
<characteristic>
<xsl:call-template name="scoreSPID">
<xsl:with-param name="characterScore" select="score"/>
</xsl:call-template>
</characteristic>
</xsl:template>
<xsl:template name="scoreSPID">
<xsl:param name="characterScore"/>
<xsl:for-each select="$characterScore">
<xsl:variable name="spid" select="SPID"/>
<score>
<xsl:for-each select="/creditRisk/pit/score[SPID eq $spid]">
<default>
<xsl:copy-of select="./node()"/>
</default>
<xsl:copy-of select="node()"/>
</xsl:for-each>
</score>
</xsl:for-each>
</xsl:template>
<xsl:template match="node()">
<xsl:apply-templates/>
</xsl:template>
How can I get the match/merge work in my xsl? Do note B3 and B4 are different dokuments in the same database.

Answer 1

<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:fn="http://www.w3.org/2005/xpath-functions"
xmlns:cts="http://marklogic.com/cts" xmlns:fff="schema://fc.fasset/functions"
exclude-result-prefixes="#all" version="2.0">
<xsl:function name="fff:mergeModelI">
<xsl:param name="characterScore"/>
<xsl:for-each select="$characterScore">
<xsl:variable name="spid" select="SPID"/>
<xsl:variable name="query"
select="cts:path-range-query('/creditRisk/pit/score/SPID', '=', $spid)"/>
<xsl:variable name="model"
select="cts:search(fn:collection('collection-name')/creditRisk/pit/score, $query)"/>
<xsl:choose>
<xsl:when test="exists($model)">
<score>
<matched>merged</matched>
<default>
<xsl:copy-of select="$model/node()"/>
</default>
<xsl:copy-of select="node()"/>
</score>
</xsl:when>
<xsl:otherwise/>
</xsl:choose>
</xsl:for-each>
</xsl:function>
<xsl:template match="characteristic">
<characteristic>
<xsl:sequence select="fff:mergeModelI(score)"/>
</characteristic>
</xsl:template>
<xsl:template match="node()">
<xsl:apply-templates/>
</xsl:template>
</xsl:transform>
If you are looking at continuous integration, the matched/merged document should be ingested in another database with distinct collection(s).
The aforesaid and data governance/auditing necessitate the match/merge operation tracking. Here I tag <matched>merged</matched> as a recourse. The matched/merged document can be populated in another database based on the tag. You can design more comprehensive canonicalization to suit your needs.

Answer 2

In the predicate filter for the for-each:
<xsl:for-each select="/creditRisk/pit/score[SPID eq spid]">
you want to filter where the SPID is equal to the variable $spid. Without the $ it is looking for a sibling element spid (which doesn't exist).
It should be:
<xsl:for-each select="/creditRisk/pit/score[SPID eq $spid]">