Problem writing a XSLT to convert XML in desired format from a table having self join

Question

Hello,
I have to write a style sheet to convert XML generated from XSQL into a different format. The query that I have is as follows.
select LEVEL depth,
'H' || hierarchy_id id,
name,
nvl2(parent_id, 'H' || parent_id, 0) parent_id,
CURSOR(select LEVEL depth,
'H' || hierarchy_id hid,
name hname,
nvl2(parent_id, 'H' || parent_id, 0) hparent_id,
decode(system_id, NULL, '0', 'S' || system_id) formatted_system_id,
system_id
from hierarchy
where parent_id = h.hierarchy_id
and system_id is not null
) as systems
from hierarchy h
where system_id is null
start with parent_id is null
connect by prior hierarchy_id = parent_id
The hierarchy table has a self join to itself. The selfjoin is on the hierarchyid and the parentid fields which is evident from the query.
Here the hierarchy table contains the parent system and also the child systems underneath. The problem is that the no. of levels that it can go deep is not fixed. The output of this in sqlplus is as follows.
Depth Hierarchyid, name parentid
1 h1 xxx <null>
2 h2 bbb h1
3 h3 ccc h2
<Cursor for systems>
hid hname hparentid formatted_system_id systemid
h4 ccc h2 s1 1
h5 ccc h2 s2 2
<Back to original data>
Depth Hierarchyid, name parentid
2 h6 ddd h1
2 h7 eee h1
The desired output required from the stylesheet is as follows
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1>
<h id=h3 name=ccc parentid=h2>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
Could some one guide me as to how to get this. I did write a stylesheet which gives me the following output.
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1/>
<h id=h3 name=ccc parentid=h2/>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
As you can see I am missing the closing of the tag on the 7th line in the desired format. I have written the following stylesheet.
<!-- Hierarchy.xsl: Transform ROWSET/ROW format to the required Hierarchy format. -->
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
<!-- Template for matching the rowset..... -->
<xsl:template match="HIERARCHY">
<HIERARCHY><xsl:apply-templates/></HIERARCHY>
</xsl:template>
<!-- Template for matching the row .... -->
<xsl:template match="HELEMENT">
<xsl:choose>
<xsl:when test="PARENT_ID=0">
<helement id="{ID}" name="{NAME}" parentid="{PARENT_ID}"/>
</xsl:when>
<xsl:when test="PARENT_ID!='0'">
<helement2 id="{ID}" name="{NAME}" parentid="{PARENT_ID}">
<xsl:for-each select="SYSTEMS/SYSTEMS_ROW">
<helement3 id="{HID}" name="{HNAME}" parentid="{HPARENT_ID}" systemid="{FORMATTED_SYSTEM_ID}">
</helement3>
</xsl:for-each>
</helement2>
</xsl:when>
<xsl:otherwise>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Is there any way of achieving this. Any help would be appreciated. I am using XSQL to generate first the basic XML output and then applying stylesheet to achieve the desired output.
Sincerely,
D

Answer 1

Hello,
I have to write a style sheet to convert XML generated from XSQL into a different format. The query that I have is as follows.
select LEVEL depth,
'H' || hierarchy_id id,
name,
nvl2(parent_id, 'H' || parent_id, 0) parent_id,
CURSOR(select LEVEL depth,
'H' || hierarchy_id hid,
name hname,
nvl2(parent_id, 'H' || parent_id, 0) hparent_id,
decode(system_id, NULL, '0', 'S' || system_id) formatted_system_id,
system_id
from hierarchy
where parent_id = h.hierarchy_id
and system_id is not null
) as systems
from hierarchy h
where system_id is null
start with parent_id is null
connect by prior hierarchy_id = parent_id
The hierarchy table has a self join to itself. The selfjoin is on the hierarchyid and the parentid fields which is evident from the query.
Here the hierarchy table contains the parent system and also the child systems underneath. The problem is that the no. of levels that it can go deep is not fixed. The output of this in sqlplus is as follows.
Depth Hierarchyid, name parentid
1 h1 xxx <null>
2 h2 bbb h1
3 h3 ccc h2
<Cursor for systems>
hid hname hparentid formatted_system_id systemid
h4 ccc h2 s1 1
h5 ccc h2 s2 2
<Back to original data>
Depth Hierarchyid, name parentid
2 h6 ddd h1
2 h7 eee h1
The desired output required from the stylesheet is as follows
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1>
<h id=h3 name=ccc parentid=h2>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
Could some one guide me as to how to get this. I did write a stylesheet which gives me the following output.
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1/>
<h id=h3 name=ccc parentid=h2/>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
As you can see I am missing the closing of the tag on the 7th line in the desired format. I have written the following stylesheet.
<!-- Hierarchy.xsl: Transform ROWSET/ROW format to the required Hierarchy format. -->
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
<!-- Template for matching the rowset..... -->
<xsl:template match="HIERARCHY">
<HIERARCHY><xsl:apply-templates/></HIERARCHY>
</xsl:template>
<!-- Template for matching the row .... -->
<xsl:template match="HELEMENT">
<xsl:choose>
<xsl:when test="PARENT_ID=0">
<helement id="{ID}" name="{NAME}" parentid="{PARENT_ID}"/>
</xsl:when>
<xsl:when test="PARENT_ID!='0'">
<helement2 id="{ID}" name="{NAME}" parentid="{PARENT_ID}">
<xsl:for-each select="SYSTEMS/SYSTEMS_ROW">
<helement3 id="{HID}" name="{HNAME}" parentid="{HPARENT_ID}" systemid="{FORMATTED_SYSTEM_ID}">
</helement3>
</xsl:for-each>
</helement2>
</xsl:when>
<xsl:otherwise>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Is there any way of achieving this. Any help would be appreciated. I am using XSQL to generate first the basic XML output and then applying stylesheet to achieve the desired output.
Sincerely,
D