Chris Frey wrote:
> Connection<MysqlDriver> con;
> Connection<PostgreSQLDriver> con2;
I'm not sure templatizing Connection is required. You could just add a
parameter to the ctor:
Connection con(new MySQLDriver, ...)
The semantic difference is that Connection has-a driver, it is not
implemented-in-terms-of-a specific driver type. (Connection clearly
could be implemented in terms of a generic driver type, which implies
inheritance, not templates.)
One benefit of my way is that you don't duplicate the code of Connection
in the binary for each concurrent driver type you use.
Another benefit is that a program could switch database types without
being rebuilt. It could have a preference file of some sort, saying
which database server is on this particular system. The program would
just pass a different DatabaseDriver subclass instance when creating the
Connection object.
The only advantage to the template method is that you wouldn't have a
pointer indirection when calling the driver. But since almost every
driver call involves a database server interaction, optimizing call
times pointless.
