perl 存储复杂数据到DBM文件

[perl]代码库

#-----------------------------
use MLDBM 'DB_File';
tie ( %HASH, 'MLDBM', [... other DBM arguments] ) or die $!;
#-----------------------------
# %hash is a tied hash
$hash {"Tom Christiansen"} = [ "book author", 'tchrist@perl.com' ];
$hash {"Tom Boutell"} = [ "shareware author", 'boutell@boutell.com' ];

# names to compare
$name1 = "Tom Christiansen";
$name2 = "Tom Boutell";

$tom1 = $hash {$name1};
# snag local pointer
$tom2 = $hash {$name2};
# and another

print "Two Toming: $tom1 $tom2\n";

Tom Toming:
ARRAY ( 0x73048 ) ARRAY ( 0x73e4c )
#-----------------------------
if ( $tom1->[0] eq $tom2->[0] &&
        $tom1->[1] eq $tom2->[1] )
{
	print "You're having runtime fun with one Tom made two.\n";
}
else
{
	print "No two Toms are ever alike.\n";
}
#-----------------------------
if ( $hash {$name1}->[0] eq $hash {$name2}->[0] &&     # INEFFICIENT
        $hash {$name1}->[1] eq $hash {$name2}->[1] )
{
	print "You're having runtime fun with one Tom made two.\n";
}
else
{
	print "No two Toms are ever alike.\n";
}
#-----------------------------
$hash {"Tom Boutell"}->[0] = "Poet Programmer";
# WRONG
#-----------------------------
$entry = $hash {"Tom Boutell"};
# RIGHT
$entry->[0] = "Poet Programmer";
$hash {"Tom Boutell"} = $entry;
#-----------------------------