#!/usr/local/bin/perl
# Jaime Prilusky, 2009
# adapted from DB_File perldoc
use warnings ;
use strict ;
use DB_File ;

  our (%h, $k, $v) ;
  my $dbFile = "fruit";
# only if we want to start from scratch
# unlink $dbFile ;

  createDatabase($dbFile);
  dumpDatabaseContent($dbFile);  # show what we have
  deleteFromDatabase($dbFile,"apple");
  dumpDatabaseContent($dbFile);  # show what we have

sub createDatabase {
  my($dbFile) = @_;
  print "create database '$dbFile' ...\n";
  tie %h, "DB_File", $dbFile, O_RDWR|O_CREAT, 0666
    or die "Cannot open file $dbFile: $!\n";

  # Add a few key/value pairs to the file
  $h{"apple"} = "red" ;
  $h{"orange"} = "orange" ;
  $h{"banana"} = "yellow" ;
  $h{"tomato"} = "red" ;
  
  untie %h ;
}

sub dumpDatabaseContent {
  my($dbFile) = @_;
  print "database '$dbFile' contents ...\n";
  tie %h, "DB_File", $dbFile, O_RDWR;
  while (($k, $v) = each %h) { print "\t$k -> $v\n" }
  untie %h ;
}

sub deleteFromDatabase {
  my($dbFile,$key) = @_;
  print "delete from database '$dbFile' key/value '$key' ...\n";
  tie %h, "DB_File", $dbFile, O_RDWR;
  if (!$h{$key}) {
    print "unable to find key $key\n";
  } else {
    delete $h{$key} ;
  }
  untie %h ;
}