Learning Visually with Examples [Electronic resources] نسخه متنی

1.

Verify that the database exists by issuing one of the following commands at the server:

list db directory 

or

list db directory show detail 

Figure F.2 shows the output for the

list db directory command.

Figure F.2 confirms that the SAMPLE database resides locally on this server since the

Directory entry type field has a value of

Indirect . If the database resides on a different server, this field would have a value of

Remote , which is not what you would want to see.

2.

Check the DB2COMM registry variable to verify that the correct communication protocol is specified by using the

db2set all command (see Figure F.3).

Figure F.3 shows that DB2COMM is set to TCPIP; therefore, the server is ready to listen for TCP/IP requests.

3.

Verify that the appropriate configuration parameters are set in the Database Manager Configuration file. Issue the

get dbm cfg command and examine the following.

• If DB2COMM=TCPIP, then SVCENAME must be set.

• If DB2COMM=NETBIOS, then NNAME must be set.

1.

Verify that the server connectivity information has been correctly entered in the node directory by using the

list node directory command.

The service name in the client's node directory is a port number that matches the port number referenced by the SVCENAME on the server. For example, the SVCENAME on the server is set to

db2c_DB2 , as shown in Figure F.4, and as we saw, this mapped to port 50000 in the server's services file. Therefore, the client needs to specify port 50000 in the node directory, as shown in Figure F.5.

Alternatively, the client can specify a service name instead of the port number in the node directory. However, this service name is to be defined at the client services file, not the server services file. For example, the node directory can have the service name

db2conn . If this is the case, then in the client's services file, you must set

db2conn to 50000:

db2conn    50000/tcp 

2.

Verify that you can ping the host name exactly as it appears in the node directory. If you cannot, that means there is problem connecting to the server. Try to ping the IP address of the server. If that works, then recatalog the node using the IP address instead of the host name and try again.

To recatalog the node directory, you need to first uncatalog the existing node:

uncatalog node  
nodename 

3.

Even if the client can reach the server, it does not necessarily mean that the client can access the port to connect to databases on the server. Sometimes, for security reasons, the server port is not open to client connections, or the port is not enabled at all. To test if a port is accessible, you can telnet to the port as follows:

telnet  
hostname or ip address  
50000 

alias in the server's database directory (see Figure F.6).

If the database resides on a host server, verify the DCS directory. Using the

list dcs directory command, ensure that the database name in the database directory matches the database name in the DCS directory (see Figure F.7). The target database name in the DCS directory must be the Location name if the host server is DB2 for z/OS and OS/390, or the RDB name if the host server is DB2 for iSeries.