The oracle database has a CONNECT statement which allows for easy traversing of hierarchically coded info:

SELECT LEVEL, SUB, SUPER
FROM   PARTS
CONNECT WITH PRIOR SUPER = SUB
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LEVEL is a builtin Oracle variable which tells you current depth of traversal. SUB and SUPER are table columns which show which parts are subordinate to others.

And of course, you can use LPAD():

SELECT, LEVEL, LPAD('   ', LEVEL, SUB), SUPER;
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to "tab over" each degree of recursion. Or write your own function to create display as needed.

Perl is nice, but server side database preprocessing can be faster and more definitional.