Creating Insert Transformations Automatically
In Chapter 12, we learned how to use the
<xsql:insert-request> element to get posted XML or HTML form
data into our database. Recall that the <xsql:insert-request>
action element has the following syntax:
<xsql:insert-request table="targettable" transform="style.xsl"/>where it is the job of the style.xsl stylesheet
to transform the inbound XML document into the canonical
ROWSET/ROW format that reflects the structure of
the targettable table or view. If
you’re like me, you tire quickly of manually creating these
“insert transform” stylesheets and you start thinking of
a way to automate their creation. You need look no further than the
effective combination of XSQL pages and XSLT to get the data we need
and XSLT to produce the “insert transform” for a given
table.
Recall that the canonical XML structure required for insert is the same structure that is produced by doing a SELECT * query over the table in question. So let’s build a simple XSQL page to do that SELECT * query over a table whose name is a parameter supplied in the request:
<?xml version="1.0"?>
<page connname="xmlbook" connection="{@connname}">
<xsql:query null-indicator="yes" xmlns:xsql="urn:oracle-xsql">
<![CDATA[
SELECT *
FROM {@table}
WHERE rownum < 2
]]>
</xsql:query>
</page>The FROM clause uses the {@table} syntax to refer
to an XSQL page parameter and is wrapped in by a
CDATA section so that none of the characters that
occur between the opening <
