MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 5: Basic ODBC Application Steps

Step 6: Disconnect from the Data Source

The final step is to disconnect from the data source, as shown in the following illustration. First, the application frees any statement handles by calling SQLFreeHandle. For more information, see "Freeing a Statement Handle" in Chapter 9, "Executing Statements."

Next, the application disconnects from the data source with SQLDisconnect and frees the connection handle with SQLFreeHandle. For more information, see "Disconnecting from a Data Source or Driver" in Chapter 6, "Connecting to a Data Source or Driver."

Finally, the application frees the environment handle with SQLFreeHandle and unloads the Driver Manager. For more information, see "Allocating the Environment Handle" in Chapter 6, "Connecting to a Data Source or Driver."