The distributed database facility allows data that has been stored and managed by one department to be used by other departments in real time, and for that data to be accessed and updated without the user having to be aware of the location of the database. This facility also allows you to distribute the workload of your business-critical corporate databases and to use the data throughout your entire company. A database can be distributed between HiRDB and DBMSs at other nodes by using the remote database access facility of DF/UX. The remote database access facility has two functions:

• Distributed client facility
• Distributed server facility

(a) Distributed client facility

The distributed client facility makes it possible to perform remote database accesses to distributed servers, using HiRDB running at the local node as a distributed client (you can perform remote database accesses to DBMS databases located at other nodes by using a HiRDB UAP that is set up on the local node). This feature can be implemented by using the distributed client facility of DF/UX.

When you create a UAP, you must code SQL statements in HiRDB, similar to the process of performing local access to a HiRDB database at the local node. You must specify in the SQL statements the table name for the distributed server and a name indicating the location of the database. For restrictions on UAP creation, see the HiRDB Version 8 UAP Development Guide.

Figure 2-17 provides an overview of the distributed client facility.

Figure 2-17 Overview of the distributed client facility

(b) Distributed server facility

Using the HiRDB running at the local node as a distributed server, it is possible to perform remote database accesses from distributed clients running at other nodes (you can also perform remote database accesses to the HiRDB database running at the local node from DBMSs running at other nodes). Such accesses can be achieved by using the distributed server facility of DF/UX. Figure 2-18 provides an overview of the distributed server facility.

Figure 2-18 Overview of the distributed server facility

Table 2-5 shows the applicability of distributed databases when HiRDB is used.

Table 2-5 Applicability of distributed databases

Type of distributed client	Type of distributed server
	HiRDB	XDM/RD	ORACLE (HI-UX/ WE2 Version)	RDB1 E2	SQL/K
HiRDB	Y1	Y	Y2	Y2	Y2
XDM/RD	Y
ORACLE (HI-UX/WE2 Version)	Y3
RDB1 E2	N
SQL/K	N

Y: A distributed server can be used.

N: A distributed server cannot be used.

: Not applicable

Notes

• Note that in the current release of HiRDB, the distributed database facility is limited to HiRDB's HP-UX and AIX 5L versions (excluding the 64-bit version of HiRDB and the POSIX library version of HiRDB). However, the facility is also supported on the Hi-UX/WE2 versions of HiRDB prior to Version 07-02, so you can run the distributed database facility with these earlier HI-UX/WE2 versions of HiRDB.
• OSI-RDA is the protocol that is used.
• XDM/RD refers to both XDM/RD and XDM/RD E2.

¹ You can build distributed databases even on different platforms. For example, you can build a distributed database on the HP-UX and AIX 5L versions of HiRDB.

² With this distributed client, distributed databases can be built only with the HP-UX versions of HiRDB.

³ With this distributed server, you can build distributed databases only with HP-UX versions of HiRDB.

For instructions on setting the environment for the distributed database facility, see the HiRDB Version 8 System Operation Guide. For details on DF/UX, see the Distributed Database System DF/UX.