dprl/model/rectify-schematron.xml

<?xml version="1.0" encoding="UTF-8"?>
<sch:schema xmlns:sch="http://www.ascc.net/xml/schematron">
    <sch:ns uri="http://www.omg.org/spec/BPMN/20100524/MODEL" prefix="bpmn"/>

    <sch:pattern> 
        <sch:title>Unique Ids</sch:title> 
        <sch:rule context="*[@id]"> 
            <sch:assert test="not(preceding::*[@id=current()/@id][1]">Id attributes should be unique in a document.</sch:assert> 
        </sch:rule> 
    </sch:pattern>

    <sch:pattern name="lane id">
        <sch:rule context="bpmn:lane">
            <sch:assert test="@id">The element lane must have an id attribute</sch:assert>
        </sch:rule>
    </sch:pattern>
    <sch:pattern name="sequenceFlow id">
        <sch:rule context="bpmn:lane">
            <sch:assert test="@id">The element sequenceFlow must have an id attribute</sch:assert>
        </sch:rule>
    </sch:pattern>
    <sch:pattern name="id obligatory for other elements">
        <sch:rule context="bpmn:[@intermediateCatchEvent,@parallelGateway,@exclusiveGateway,@inclusiveGateway,@startEvent,@endEvent,@task">
            <sch:assert test="@id">The element intermediateCatchEvent, parallelGateway, exclusiveGateway, inclusiveGateway, startEvent, endEvent, task must have an id attribute</sch:assert>
        </sch:rule>
    </sch:pattern>

    <sch:pattern name="Check source-target constraints">
        <sch:rule context="bpmn:sequenceFlow">
            <sch:assert test="(@sourceRef = '*' and @targetRef = '*') and @sourceRef != ''">Check the target exists.</sch:assert>
        </sch:rule>
    </sch:pattern>
</sch:schema>