edit following constants in database.php or include them from another file:
define('DB_HOST', 'db_host');
define('DB_PORT', '');
define('DB_USERNAME', 'db_user');
define('DB_PASSWORD', 'db_pass');
define('DB_NAME', 'db_name');
define('DB_CHARSET', 'utf8');
$helper = new DataInsertHelper('table_name');
$helper->addInteger('field_1', 1);
$helper->addString('field_2', 'string value');
$result = $helper->execute();
// this operation is same as executing SQL:
// INSERT INTO table_name(field_1,field_2) VALUES(1,'string value');
$helper = new DataDeleteHelper('table_name');
$helper->addConditionEqualString('username', 'foo');
$result = $helper->execute();
// this operation is same as executing SQL:
// DELETE FROM table_name WHERE username='foo';
$helper = new DataUpdateHelper('table_name');
$helper->addConditionEqual('user_id', 15);
$helper->setString('username', 'bar');
$result = $helper->execute();
// this operation is same as executing SQL:
// UPDATE table_name SET username='bar' WHERE user_id=15;
$helper = new DataQueryHelper('table_name');
$helper->addConditionInKeywords('user_id',4);
$helper->addOrderDesc('user_id');
$result = $helper->query();
// the $result is an associated array which it's key is database field name and value is the queried value from database.
// this operation is same as executing SQL:
// SELECT * FROM table_name WHERE user_id=4 ORDER BY user_id DESC