The Single-Tier ODBC Drivers for PostgreSQL are a single component installed on a data-consuming machine - depending on the architecture in which the driver is deployed, either a client such as a desktop, a workstation or an application-server machine. No components need be installed on the database server.
The OpenLink Single-Tier Drivers for PostgreSQL are a Type-B class of driver developed using the PostgreSQL network (wire) protocol interface, thereby avoiding the need for the installation of any PostgreSQL-specific client networking software.