Basically, contructor of CRUD statmenets with SQL.

*SAMPLE USAGE*

$queryBuilder = new DbQueryBuilder();
# INSERT:
$queryBuilder->insert('mydatabase.mytable', array('username' => 'Nemoden', 'age' => 25));
// INSERT INTO `mydatabase`.`mytable` (`username`, `age`) VALUES (:username, :age)
$queryBuilder->getBindParams();
// array(':username' => 'Nemoden', ':age' => 25)

We can add ON DUPLICATE KEY UPDATE statement on the end of our INSERT statmenet:
$queryBuilder->onDuplicate(array('cnt' => new DbExpression('cnt+1'));

# UPDATE:
$queryBuilder->update('mydatabase.mytable', 
                      array('age' => 26), 
                      array('conditions' => 'username = :username'))
             ->bindParams(array(':username' => 'Nemoden'));
// UPDATE `mydatabase`.`mytable` SET `age` = :age WHERE username = :username 
// note that username does not uses backticks! It's because it is set explicitly in condition
$queryBuilder->getBindParams();
// array(':age' => 26, ':username' => 'Nemoden')
Placeholder age was added automatically, - this is how update method works - it strives to normalize everything it can.
In case of username, we had to add it by hand since DbCriteria can not deal with strings parsing and fetching placeholders
and corellating corresponding values to them. If it were true, we had to do some extra-work to set up conditions.

DELETE and SELECT work in the similar way, you can figure out how to SELECT everything from `mydatabase`.`mytable`?
$queryBuilder->select('mydatabase.mytable');

You can add criteria whenever you want:
$queryBuilder->addCriteria($criteria);

And criteria is either an array or instance of DbCriteria:
$criteria = array(
  'conditions' => 'age = 25',
  'having' => 'salary > 10000',
  'limit' => 10,
);
Behind the scenes, DbQueryBuilder::addCriteria feed this array to DbCriteria to get an instance.


Pretty simple, huh?