Troubleshooting Guide

Overview of Client Connectivity

This section provides an overview of how DB2 clients connect to DB2 servers. This information can help you understand the various areas where connectivity problems typically occur.

Client workstations are connected to a DB2 server through a communication protocol (for example, TCP/IP, APPC, NetBIOS, or IPX/SPX). This connection enables applications to run on a client and interact with DB2. Examples of applications are Lotus Approach, Microsoft Access, or user-written applications.

When an application needs to access a database, it uses a CONNECT statement. The database alias identified in the CONNECT statement references an entry in the client's database directory. This entry contains these important elements:

• The actual name of the database on the server

• If the database is local, the path (and drive on Intel systems) where the local database directory resides

• If the database is remote, the name of a corresponding entry in the node directory. The node directory provides communications information to form the connection.

• The local alias name for the database. The local database alias name and the server database name are usually the same. However, to access databases with the same name that reside on different systems, you must give each database a different local alias name so that your applications can tell them apart.

The node directory indicates where the database is physically located. Each node directory entry specifies which network communication protocol to use to connect to the database, and the protocol parameter values required to make the connection.

The database directory and node directory ensure that access to a database is transparent to users and applications, regardless of where the database physically resides. If a database has been cataloged correctly on the client, you can connect to the database if you know the local database alias name.

See the Quick Beginnings guide for your platform for details on maintaining the information in the database and node directories.

In addition to the directories, the following are required for client communications to a DB2 server:

• Database manager configuration parameters on the server.

• DB2 registry values. On Windows NT, Windows 95, OS/2, and UNIX-based systems, environment variables are stored in a DB2 registry. Update them with the db2set command. For information on the DB2 registry values available on your operating system, type db2set -lr.

  (On Windows 3.1, environment variables are stored in the db2.ini file and can be updated by editing this file. On Macintosh systems, there is a DB2 preferences file.)

• The db2cli.ini and odbc.ini files are ASCII files that store values for DB2 CLI configuration. For information, see the CLI Guide and Reference.

Refer to the Quick Beginnings guide for your platform for details on client connectivity.

Client Connectivity Tools

After installing DB2, you can use the following tools on the OS/2, Windows NT, or Windows 95 operating systems to connect a client to a database on a server:

Setup Communications

Sets up communications for server instances, including those that are remote UNIX-based. To update communications for a server instance, select its object from the Control Center and select Setup Communications from the pop-up menu.

Note that the communication protocol stack must already be set up.

Client Configuration Assistant

Lets you define connections to databases so that the databases can be used by applications. This tool is available for Windows NT, Windows 95, and OS/2 servers and clients. (For Windows 3.x, the Client Setup tool is available instead.)

Alternatively, use the command line processor to set up clients on UNIX-based environments. See the Command Reference for information on the CATALOG DATABASE and CATALOG protocol NODE commands.

For more information, see your Quick Beginnings guide.

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