Multiple database support

[CommandString]

public function switchDatabase(??? $database): void;

[freezemage0]

I think this method should instantiate a new DriverInterface instance instead of changing the internal PDO object state.

Consider the situation where multiple high-level classes depend on the same PDODriver instance, which was injected at the entry-point.

Changing database in one of those high-level classes will change database everywhere, because objects are always passed-by-reference. This will introduce an unexpected behavior.

However, this behavior cannot be achieved easily in current PDODriver state, because database name is a part of DSN, which is a string. The only way to implement this switchDatabase() method is to make DSN value object. Then we could re-use this DSN to make a new PDO connection inside DriverInterface::switchDatabase() method and return a new DriverInterface instance.

[CommandString]

Then we could re-use this DSN to make a new PDO connection inside DriverInterface::switchDatabase()

We'd also need to store the username and password if we're attempting to reconnect. I was personally thinking of having DriverCollection since it seems wrong to have the Driver deal with juggling two connections

interface DriverCollection {
   public function addDriver(string $name, DriverInterface $driver): self;
   public function getDriver(string $name): ?DriverInterface;
   // etc etc
}