As well as providing a relational database to store your data, DB2 lets you administer requests to query, update, insert, or delete data from local or remote client applications.
DB2 Universal Database includes tools that enable you to tune performance, access remote DB2 servers, manage all servers from a single site, develop powerful applications, and process SQL queries. These tools are described in "Administering Databases with DB2 Tools".
The DB2 Universal Database can run applications locally and can be accessed by applications running on remote clients that have the DB2 Client Application Enabler installed. The DB2 Client Application Enabler provides a run-time environment that enables client applications to access one or more remote databases. Software on the DB2 Client Pack CD-ROM provides support for clients on the following operating systems:
The Client Application Enabler for DOS V1.2 is available only from the Web. See Chapter 7. "Installing DB2 Clients" for information on how to download the DOS client.
Figure 1 shows a DB2 Universal Database with local applications and applications running on remote clients. Either DB2 Workgroup Edition or DB2 Enterprise Edition is installed on the server. This is the system that contains your databases. Any applications running on this system are known as local applications. The client systems need one of the DB2 Client Application Enabler products installed, which allows applications to access the data on the remote server system.
Figure 1. DB2 with Local Applications and Remote Clients
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In addition to accepting requests from the clients listed above, DB2 Universal Database has the DRDA Application Server feature built in. It accepts requests from MVS, OS/400, VM, and other DRDA clients. (The DRDA Application Server feature is not supported on the HP-UX platform.) Refer to the Administration Guide for more information.
Once a network is operational and protocols are functional on the workstations, LAN-to-LAN connections between DB2 servers and clients require no additional software.
For example, you can have a DB2 server on a Windows NT workstation that is connected to a LAN located in Montreal, and another DB2 server on a UNIX system connected to a LAN located in Toronto. As long as there is a connection between the two LANs, clients on either network can access either server. See Figure 2.
Figure 2. Accessing Data on Multiple Servers
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Within a single transaction, databases on both servers are accessed and updated, and the integrity of the data on both servers is maintained. This is commonly known as two-phase commit, or distributed-unit-of-work access. Refer to the Administration Guide for more information.