The JDBC Driver does not require a user ID and password to establish a connection when the Data Access Server (DAS) is running on the same machine as the Java client. When a userID/password is not provided, the Java client process user ID is used to establish the DBMS connection. If the target database specification includes a VNODE (see page Tools for Defining Vnodes), the VNODE login information is used to access the DBMS machine. Optionally, a userID/password can be provided and is handled as described below.

When the Java client and DAS are on different machines, a user ID and password are required to establish a connection to the DBMS. If the DAS and DBMS server are running in the same Ingres instance (no VNODE in target database specification), the userID/password is used to validate access to the DAS/DBMS machine.

When the DAS and DBMS servers are on different machines, a VNODE is required in the target database specification. The VNODE provides the connection and (optionally) login information needed to establish the DBMS connection.

The driver property vnode_usage determines how the VNODE is used to access the DBMS. The vnode_usage property also determines the context (DAS or DBMS) in which the application userID/password is used. VNODE usage without a userID/password is described above. If the target database specification does not contain a VNODE, the vnode_usage property is ignored.

When vnode_usage is set to 'connect', only global VNODE connection information is used to establish the DBMS connection. The application-provided user ID and password are used in the DBMS context to access the DBMS machine.

When vnode_usage is set to 'login', both connection and login VNODE information is used to access the DBMS machine. The application-provided user ID and password are used in the DAS context, allowing access to private and global VNODEs.