http://www.oracle.com/technology/products/ias/bpel/pdf/orabpel-Tutorial3-DataManipulationTutorial.pdf
some other links:
http://jsexton0.blogspot.com/2009/01/openesb-bpel-assignment-tips.html
http://n2.nabble.com/ignoreMissingFromData-usage-td2474810.html
btw, all this research was due to the following error with open esb + glassfish combination:
Caused by: com.sun.jbi.engine.bpel.core.bpel.exception.StandardException: I18N: BPCOR-3023: Selection Failure occurred in BPEL({http://enterprise.netbeans.org/bpel/Balistika2010Bpel/IncidentRegistration}IncidentRegistration) at line 71!
BPCOR-6129:Line Number is 69
BPCOR-6130:Activity Name is AssignExtractDaimData
at com.sun.jbi.engine.bpel.core.bpel.engine.impl.BPELInterpreter.createVirtualFaultUnit(BPELInterpreter.java:235)
at com.sun.jbi.engine.bpel.core.bpel.engine.impl.BPELInterpreter.execute(BPELInterpreter.java:203)
issue about
ignoreMissingData attribute on assign elementhttps://open-jbi-components.dev.java.net/issues/show_bug.cgi?id=181