The Microsoft SQL Server dbExpress driver will automatically call coinitialize when the driver is loaded. If this initial call to counitialize succeeds, the driver will also:

1. Call couninitialize when the driver is unloaded.
2. Call coinitialize when a new connection is made.
3. Call counitialize when a connection is closed.

The apartment threading model is used to all automatic calls to coinitialize made by the driver.

If a different threading model is needed, or there are any other problems using this driver with a multiple threaded application, it is best it the application calls coinitialize and counitialize for all threads that use this driver:

1. Call coinitialize when the application starts and couninitialize before the application exits.
2. Call coinitialize when a secondary thread starts and couninitialize before the secondary thread exits.