sub new {
    my $class = shift;
    my $hash_ref = shift;
    my $self = {
        value => '100',
        color => 'charcoal',
    };
    @$self{keys %$hash_ref} = (values %$hash_ref) if (defined %$hash_r
+ef);
    bless($self, $class);
}
[download]

Still, it's a pretty nice technique, and there's no reason it has to be limited to constructors. In your case, it just might work.

as for the second part, you should check out placeholder variables if you're using DBI. for more info, check out: What are placeholders in DBI, and why would I want to use them?.

sub Whatever
{
    # Optional test of the arguments. Good for catching programmer err
+ors. 
    # Not that anyone here ever makes any. 8-)
    die 'Takes a hash ref' if @_ and grep { "HASH" ne ref } @_;

    # Set up the defaults here:
    my %args = ( KEY1 => 'default value', KEY2 => 'etc...' );

    # And process the args.
    my $index = @_; # Intentionally reverse the order.
                    # The first hash thus has precedence.
    while( --$index >= $[ )
    {
        $args{$_} = $_[$index]->{$_} for keys %{$_[$index]}
    }

    # Do stuff with %args.
}
[download]

Note that I keep saying "passed in hash", what I should say is "hash that the passed in hashref references", but I'm lazy. Then again I added this comment... sigh

$values{VALUE1} ||= "Default Value";
$values{VALUE2} ||= "Default Value";
[download]

not sure what database you're using or if these 'default values' would change from time to time depending on context, but you could let the database take care of that for you. Most DBs will let you assign defaults for columns. I'm an Oracle guy and I do this in a few places and it works like a charm. obviously, this is only useful if these are true 'defaults' that would always be the same in the absence of real data to insert.

-- I'm a solipsist, and so is everyone else. (think about it)

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

use strict;

my %hsh = (a=>1,c=>3,d=>undef);

my %hsh1 = myfunc(%hsh);

while (my ($key, $value) = each %hsh1) {
 print "$key=$value\n";
}

sub myfunc {
 my %hsh = @_;
 my %dflt_values = (a=>0,b=>0,c=>0,d=>0);
 $hsh{$_} = $dflt_values{$_} for grep { not defined $hsh{$_} } keys %d
+flt_values;
 %hsh;
}
[download]

In reply to your PS:

If you have really sophisticated DB scheme and want to use OO-Perl abstraction of its structure instead of writing long SQL queries look at BingoX or Alzabo.

Today restrictions: the former works only with RDBMS which support transactions (read - works with Postgres but does not work with MySQL), the latter - only with MySQL.

Another one that seems very interesting (I haven't actually used it myself) is Tangram.

http://tangram.sourceforge.net/

/J