This class implements a database abstraction layer similar to PDO. It comes with a base class that provides an interface to the basic database access wrapper functionality. Drivers that provide the actual implementation of the database access functionality should implement a sub-class of the main interface class. The main interface class provides functions for: - Establishing connections - Executing queries - Set query result range limits - Prepared queries - Transaction management Result sets can be retrieved with iterators. Database access errors are handled with exceptions.