#!/usr/perl/bin/perl -w

# Reads in tables in random order, and sorts out the foreign key references
# by using a topological sort.

use strict;
use Graph;

{
    my $graph = Graph->new;
    my %table_text;
    my $table;
    
    while (<>) {   
        
        if (/CREATE\s+TABLE\s+(\w+)/i) {
            $table = $1;     
        }
        
        push @{ $table_text{$table} }, $_ if (defined($table));    
        if (/references\s+(\w+)/i) {
            my $table_ref = $1;
            if (! ($table_ref eq $table) ) {
                $graph->add_edge($table_ref, $table);
            }
        }
    }
    
    my @ts = $graph->topological_sort;
    foreach my $table_name (@ts) {
        my @table_rows = @{ $table_text{$table_name} };
        foreach (@table_rows) {
            print "$_";   
        }
    }
} # end of main

1;

__END__