Schematron and Namespaces

Roger Costello

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Namespaces

• In the examples considered up till now the XML instance documents did not use namespaces.
• Now let's consider creating Schematron schemas for XML instance documents that use namespaces

Example

• Here's the classification example that we saw earlier, but it is modified so that all the elements are in a (default) namespace:

1. <?xml version="1.0"?>
2. <Document xmlns="http://www.example.org"
3. classification="secret">
4. <Para classification="unclassified">
5. One if by land, two if by sea;
6. </Para>
7. </Document>

Specifying the Namespace

• At the beginning of the Schematron schema add a <sch:ns> element. It has two attributes: uri and prefix. With uri you specify a namespace, and with prefix you associate a prefix with the namespace.

1. <?xml version="1.0"?>
2. <sch:schema xmlns:sch="http://www.ascc.net/xml/schematron">
3. <sch:ns uri="http://www.example.org"
4. prefix="ex" />
5. <sch:pattern name="Security Classification Policy">...</sch:pattern>
6. </sch:schema>

Rule

• The value of the context attribute must use the prefix:

1. <sch:rule context="ex:Para[@classification='top-secret']">
2. ...
3. </sch:rule>

• Read as: this rule applies to a Para element in the ex namespace (http://www.example.org). In particular, it applies to a Para element that has a classification attribute whose value is 'top-secret'.

Assertion

• The assertion's XPath expression must use the prefix:

1. <sch:assert test="/ex:Document/@classification='top-secret'">
2. ...
3. </sch:assert>

• Read as: I assert that the classification attribute of the Document element in the ex namespace must equal 'top-secret'.

Schematron Schema

• View check-classifications.sch (example05 folder).

Validate

• Validate valid-document.xml (example05 folder) against the Schematron schema.
• Validate invalid-document.xml (example05 folder) against the Schematron schema.
• Use both Oxygen XML and Topologi to do the validation.

Lab 5

• Recall the Reserved Word Filter: For the instance document to be valid it must not contain these words:
  • SCRIPT
  • FUNCTION
• I added a namespace to valid-document.xml and invalid-document.xml (both in lab05 folder).
• Modify check-reserved-words.sch (lab05 folder) to take into account the namespaces in the XML instance documents.
• Validate both XML instance documents using Oxygen XML and Topologi.