To access a remote database, the HiRDB of the distributed client must connect to the DBMS that acts as the distributed server. The facility for accessing the distributed server (distributed RD-node) of another node using the HiRDB of the local node as the distributed client (default RD-node) is called the distributed client facility.

The distributed client facility is characterized by the following two features:

• The distributed client facility enables the HiRDB to connect automatically to a DBMS at another node, so a UAP for connecting to the DBMS at the other node is not required.
• It is possible to simultaneously access a remote database and the local database from a single UAP (note, however, that if the remote database and the local database are updated in a single transaction, transaction compatibility is not guaranteed).

The logical connection from a UAP to an RD-node for executing SQL statements is called an SQL connection. The SQL connection to the default RD-node is called the default SQL connection.

An SQL connection includes the authorization identifier for privilege checking at the connection-destination RD-node. This authorization identifier can be specified individually for each SQL connection.

Figure 11-1 shows the distributed database connection format.

Figure 11-1 Distributed database connection format