Is the table ID unique per node, per workflow, per execution? Under what circumstances (if any) might a table ID be duplicated by a different node or execution?
(What I really want is the Node ID but I understand that this is not accessible - based on my recollection of an earlier discussion. The reason is to have a unique handle per instance of a node in a workflow which can be passed to third party software.)
I suggest to not use any KNIME internals such as the NodeID (which can also change between closing and opening a workflow).
You could have a member in your NodeModel class (for instance of class java.util.UUID) that is assigned upon object creation. If you need to retain the ID beyond closing/opening KNIME you will need to save the ID as part of the internals.