ORA-01400: cannot insert NULL into ("SCHEMA"."JENKINS_BUILD_NODE"."NAME")

[evbruno]

Oracle treats empty strings as NULL, so it can't insert when running on "master node", throwing org.hibernate.exception.ConstraintViolationException.

Returning an empty string when on master is the behavior documented here http://javadoc.jenkins-ci.org/hudson/model/Slave.html#getNodeName()

I had to change the constraint for that, but I think displaying something like "(master)" would be nicer.

Thanks