#!/usr/bin/perl -w

use strict;

my $rdb={
	'table a' => {
		'aa' => {
			data => { key1=>'val', key3=>'val',key2=>'val', },
			parent => '',
			children =>  {
				'table b' =>  {
					'ab' => "TBD",
				},
				'table c' =>  {
					'ac' => "TBD",
				},
			}
		},
		'ba' => {
			data => { key1=>'val', key3=>'val',key2=>'val', },
			parent => '',
			children =>  {
				'table b' =>  {
					'bb' => "TBD",
				},
				'table c' =>  {
					'bc' => "TBD",
				},
			}
		},

	},
	'table b' => {
		'ab' => {
			data => { nonsense => 'foo' },
			parent => 'aa',
			children => {},
		},
		'bb' => {
			data => { morenonsense => 'foo' },
			parent => 'bb',
			children => {},
		},
	},
	'table c' => {
		'ac' => {
			data => { keyi => 'val' },
			parent => 'aa',
			children => {
				'table d' => {
					'ae' => "TBD",
					'af' => "TBD",
				},
				'table e' => {
					'ag' => "TBD",
				},
			},
		},
		'bc' => {
			data => { keyi => 'val' },
			parent => 'bb',
			children => {
				'table d' => {
					'be' => "TBD",
					'bf' => "TBD",
				},
				'table e' => {
					'bg' => "TBD",
					'bh' => "TBD",
				},
			},
		},

	},
	'table d' => {
		'ae' => {
			data => { k => 'v', k2 => 'v', k3 => 'v' },
			parent => 'ac',
			children => {},
		},
		'af' => {
			data => { k => 'x', k2 => 'x', k3 => 'x' },
			parent => 'ac',
			children => {},
		},
		'be' => {
			data => { k => 'v', k2 => 'v', k3 => 'v' },
			parent => 'bc',
			children => {},
		},
		'bf' => {
			data => { k => 'x', k2 => 'x', k3 => 'x' },
			parent => 'bc',
			children => {},
		},
	},
	'table e' => {
		'ag' => {
			data => { f => 'b', b => 'k' },
			parent => 'ac',
			children => {},
		},
		'bg' => {
			data => { f => 'b', b => 'k' },
			parent => 'bc',
			children => {},
		},
		'bh' => {
			data => { f => 'b', b => 'k' },
			parent => 'bc',
			children => {},
		},
	}
};
# Fixes the "TBD" above
$rdb->{'table c'}->{ac}->{children}->{'table d'}->{ae}=
      $rdb->{'table d'}->{ae};
$rdb->{'table c'}->{ac}->{children}->{'table d'}->{af}=
      $rdb->{'table d'}->{af};
$rdb->{'table c'}->{ac}->{children}->{'table e'}->{ag}=
      $rdb->{'table e'}->{ag};
$rdb->{'table a'}->{aa}->{children}->{'table b'}->{ab}=
      $rdb->{'table b'}->{ab};
$rdb->{'table a'}->{aa}->{children}->{'table c'}->{ac}=
      $rdb->{'table c'}->{ac};
$rdb->{'table c'}->{bc}->{children}->{'table d'}->{be}=
      $rdb->{'table d'}->{be};
$rdb->{'table c'}->{bc}->{children}->{'table d'}->{bf}=
      $rdb->{'table d'}->{bf};
$rdb->{'table c'}->{bc}->{children}->{'table e'}->{bg}=
      $rdb->{'table e'}->{bg};
$rdb->{'table c'}->{bc}->{children}->{'table e'}->{bh}=
      $rdb->{'table e'}->{bh};
$rdb->{'table a'}->{ba}->{children}->{'table b'}->{bb}=
      $rdb->{'table b'}->{bb};
$rdb->{'table a'}->{ba}->{children}->{'table c'}->{bc}=
      $rdb->{'table c'}->{bc};

# Given $rdb and the key "table a", traverse the structures
# so that you produce the records of:
#
# 	aa ab ac ag ae
# 	aa ab ac ag af
# 	ba bb bc bg be
# 	ba bb bc bg bf
# 	ba bb bc bh be
# 	ba bb bc bh bf
#
# (These can be arrays of arrays or arrays of hashes
#  or arrays of strings or whatever....
#  but any column MUST only contain things of the same kind)
#
# Note that:
#    * each a record from each table is represented in 
#      each "record" produced
#    * multiple records within a table are noted once for 
#      each permutation
#      (ae and af above)
#    * subsequent table names are not known: you're given 
#      only the first one.
#    * the keys within the hashes are guaranteed to be 
#      unique.
#    * the data is not important.
#    * the keys (aa, ab, bb) follow no set pattern and are 
#      strictly coincidental just in this example.
#    * each record will join with the proper number of 
#      tables.
#    * be prepared to have "table a" be the one and only 
#      table (boundaries!)
#
# NO HARD WIRING, except for the initial table name.
#
# [I think I keyed these tables in right.]