# a new record to be inserted
my %user_rec = (
				first_name => 'Foo',
				last_name => 'Bar',
				phone => '12345678',
				address => '123 Foo St',
				);

##
## . . . some code here . . .
##

# possibly somewhere in an add_db_user() sub
# ...
my @fields = keys %user_rec;
my @values = @user_rec{@fields};
my $placeholders = join(",", ("?") x scalar @fields);

my $sql = sprintf(qq~
				INSERT INTO user(%s) VALUES(%s)
				~, join(",", @fields), $placeholders);

my $sth = $dbh->prepare($sql);
$sth->execute(@values);