I'm trying to create a customization layer for the DocBook 5.0 rng schema in which I constrain the legal values for the security attribute to an enumerated set of values. From tutorials I've read it seems I'm supposed to redefine db.security.attribute as follows:
Code: Select all
<define name="db.security.attribute">
<attribute name="security">
<a:documentation>Security level of this element.</a:documentation>
<choice>
<value>internal</value>
<a:documentation>This element contains internal-only content.</a:documentation>
<value>reviewer</value>
<a:documentation>This element contains reviewer-content.</a:documentation>
<value>external</value>
<a:documentation>This element contains external content and will be published in all version of the docuemnt.</a:documentation>
<value>writeronly</value>
<a:documentation>This element contains writeronly content and will not be published in external, internal, or reviewer versions of the document.</a:documentation>
</choice>
</attribute>
</define>
However, if I add the code above to my customization, Oxygen/Jing complains that <define> for db.security.attribute must have a combine attribute (with a value of interleave or choice). Adding combine="interleave" also gives an error. There's no error if I add combine="choice" but it also doesn't constrain the security attribute and considers the doc valid with any value for security.
How do I completely override a definition from the base schema in my customization layer?
Thanks,
David