my %Q = CGI::Vars();
...
$id_cust = AddCusomer($Q{login}, $Q{pass}, $Q{name}, $Q{email}, ...)
    if $Q{pass} eq $Q{confirmpass};
...
sub AddCustomer {
    my ($login, $pass, $name, $email, ...) = @_;
    $dbh->do("INSERT INTO Customer SET login=?, pass=?, name=?,
        email=?, ...", undef, $login, $pass, $name, $email, ...)
        or return;
    $dbh->selectrow_array("SELECT LAST_INSERT_ID()");
}

##</code><code>##

my %Q = CGI::Vars();
...
$id_cust=$dbh->Insert("Customer", \%Q) if $Q{pass} eq $Q{confirmpass};

##</code><code>##

# CREATE TABLE Customer (
#       id_cust int auto_increment primary key,
#       login varchar(255) not null,
#       pass varchar(255) not null,
#       name varchar(255) not null,
#       email varchar(255) not null,
#   ) ;

# INSERT INTO Customer SET login='powerman', pass='11111',
#   name='Alex', email='root@localhost' ;
# SELECT LAST_INSERT_ID() ;
%Q = (
    login   => "powerman",
    pass    => "11111",
    name    => "Alex",
    email   => "root@localhost",
    BADKEY  => "QWEQWE",
    );
$id_cust = $dbh->Insert("Customer", \%Q);

# UPDATE Customer SET pass='22222', name='Alex Efros'
#   WHERE id_cust=1 ;
%Q = (
    id_cust => 1,
    pass    => '22222',
    name    => 'Alex Efros',
    );
$dbh->Update("Customer", \%Q);

# REPLACE INTO Customer SET id_cust=1, pass='33333' ;
$dbh->Replace("Customer", {id_cust=>1, pass=>'33333'});

# DELETE FROM Customer WHERE login='powerman' AND pass='33333' ;
$dbh->Delete("Customer", {login=>"powerman", pass=>"33333"});

# SELECT id_cust FROM Customer WHERE login='powerman' AND pass='33333' ;
$id_cust = $dbh->ID("Customer", {login=>'powerman', pass=>'33333'})

# SELECT count(*) as __count FROM Customer
$count = $dbh->Count("Customer");

# SELECT * FROM Customer
@all_customers = $dbh->Select("Customer");

# SELECT * FROM Customer WHERE id_cust=1 ;
$Cust = $dbh->Select("Customer", {id_cust=>1});

##</code><code>##

# CREATE TABLE Cust (
#       id_cust int auto_increment primary key,
#       id_country int,
#       age int,
#       join_date datetime,
#       _balance decimal(8,2),
#   );
#   CREATE TABLE SelectedGoods (
#       id_sg int auto_increment primary key,
#       id_cust int,
#       id_goods int,
#   );
#   CREATE TABLE Goods (
#       id_goods int auto_increment primary key,
#       goods varchar(255) not null,
#       cost decimal(8,2) not null,
#   );
#   CREATE TABLE Country (
#       id_country int auto_increment primary key,
#       country varchar(255) not null,
#   );

# SELECT
#   Cust.id_cust, Cust.id_country, Cust.age,
#   Cust.join_date, Cust._balance,
#   SelectedGoods.id_sg, SelectedGoods.id_cust,
#   SelectedGoods.id_goods,
#   Goods.goods, Goods.cost,
#   Country.country
# FROM
#   Cust
#   INNER JOIN SelectedGoods ON (Cust.id_cust = SelectedGoods.id_cust)
#   INNER JOIN Goods ON (SelectedGoods.id_goods = Goods.id_goods)
#   INNER JOIN Country ON (Cust.id_country = Country.id_country)
# WHERE
#   Country.country =  'Ukraine'    AND
#   Cust.age        >= 25           AND
#   Cust.join_date  >= DATE_ADD(NOW(), INTERVAL -1 DAY) AND
#   Cust._balance   >  5.50         AND
#   Goods.goods     IN ('Monitor LG','CDROM 52x')
# ORDER BY
#   Cust._balance DESC,
#   Cust.age ASC ;
%Q = (
    country             => 'Ukraine',
    age__ge             => 25,
    join_date__date_ge  => "-1 DAY",
    _balance__gt        => 5.50,
    goods               => ["Monitor LG", "CDROM 52x"],
    -order              => ["_balance DESC", "age"],
    );
@search_result = $dbh->Select(["Customer", "SelectedGoods",
    "Goods", "Country"], \%Q);

##</code><code>##

$dbh->Update("Customer", \%Q);

##</code><code>##

%Q = CGI::Vars();
delete $Q{$_} for grep {m/^_/} keys %Q;

##</code><code>##

$Q{_balance} = $Q{Set_balance} if $Admin and $Q{Set_balance};
$dbh->Insert("Customer", \%Q);

##</code><code>##

$Q{_balance} = $Q{Set_balance} if $Admin and $Q{Set_balance};
$dbh->Insert("Customer", {%Q, id_cust=>$CustID});