DB2 CONNECT BY PRIOR composite key

I wish to use CONNECT BY using a composite key but haven't been able to get it to work.

This article (https://developer.ibm.com/articles/i-db2connectby/) explains that each key column must be prefixed with the PRIOR operator. However, the example qualifies the keys, but doesn't demonstrate how the tables are qualified.

Select 202 Boss, Employee, Name
From Staff
Start with Boss = 202
Connect By Boss = Prior Employee;

If the join key is a composite key, each key column must be prefixed with the PRIOR operator:

CONNECT BY PRIOR a.Department = b.Department

AND PRIOR Employee = Boss

How do you use CONNECT BY using composite keys?

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