analytics/informix/extend/spatial.8.22.FC2/examples/gml

GML Examples
================

This directory contains sql scripts which show, by example, how to use
the GML features of Spatial DataBlade. You can run any of these
scripts using a SQL editor such as DB-Access, or SQLEditor on NT clients.

Note: DB-Access ignores formatting characters inserted in the result,
instead it inserts a newline after each 65 output characters. This
algorithm clashes with the way SE_AsGML() outputs text, and the results
may look garbled.


XML Validation
----------------
Without proper headers/trailing tags, the SE_AsGML() UDR does not produce
an XML document, but just a fragment. An element in a well-formed XML
document that contains SE_AsGML() output should have attributes that
relate to the GML schema and other extension schema documents if
applicable. You may validate the document using a schema-aware parser.

The file se_asgml.xml contains GML fragments embedded in a
element. Here is how to use Apache Xerces-J.1.4.1 to validate this
se_asgml.xml (make sure the files xerces.jar and xercesSamples.jar are in
your CLASSPATH):

java dom.DOMCount -v se_asgml.xml

Note: the validation will generate the following error message:

'The error 'Element type "document" must be declared.'

This happens because a "document" element that is not defined elsewhere
is used to enclose all the GML fragments. In a real application, it will
be replaced by an application-defined element.