Example: XML export for update

Here is an example of a constraint that calls the XML export method, and updates a database column with the result of the INVOKE statement.

Whenever a person is updated, the fact that this PERSON record is updated is stored in XML format in the XMLupdate column of the PERSON_XML_LOG table.

UPDATE     person_xml_log pxl
SET        pxl.XMLupdate =
(
     INVOKE     xml.export
     WITH
     SELECT     'Update' ExecutionType
     ,          *
     ,          OLD(*)
     FROM       person p
     WHERE      p.id = pxl.person_id
)

After an update of "John Smith" to "Johnny Smith", the XMLupdate column of the PERSON_XML_LOG table contains:

NOTES:

•The 'Update' execution type is only useful in constraints in combination with old values.

•The execution type is the same for all exported row elements.