Most problems arise during the initial connection of the JDBC
client to the database. For this reason, we shall first completely
describe the steps that occur during the connection process, and
mention some common problems that can arise.
Step 1. Loading the HP Driver for JDBC Class Files
If this step fails, the most likely cause is that
the Java CLASSPATH environment variable has not been set correctly.
Other possible causes include the driver files not
being installed, or unreadable or corrupt driver files.
Step 2. Loading the Network Components
If this step fails, it could mean a bad network
connection, or the client not being connected to the network.
Step 3. Loading the Specified Server Name
If this step fails, the most likely cause is either
an incorrect or invalid server name, an unreachable server (network
down, or outside firewall), or a down server. The user can try to
use other methods to reach the server such as ping, telnet, or ftp.
Step 4. Connecting to the 31700 or the Specified
Port Number
If this step
fails, it means that there either was no process listening on that
port number, or something other than the JDBC Monitor was listening
on that port number. A server administrator can verify that the
JDBC Monitor process is running and accepting connections on the
default or other port number.
Step 5. Validating the Userid and Password
If this step fails, the most likely cause is an
incorrect userid, or invalid passwords for the userid. You can attempt
to use ftp or telnet to verify that the userid and passwords are
valid.
Step 6. Spawning a Server Process by the JDBC Monitor
If this step fails (some resource limit is reached
on the server), the monitor logs should indicate the reason for
the failure.
Step 7. Switching to the Effective User
Once the process is spawned, the monitor switches
the effective user id to the user that was supplied in the user
validation. This ensures that the user only has the privileges assigned
to the user. If this step fails, the most likely cause is that the
monitor was not started by "root," the superuser
for HP-UX, or a user with the PM capabilities for MPE/iX. The user
can log on to the server and verify that the monitor process was
started by the correct user and has the proper capabilities.
Step 8. Executing the JDBC Server by the Spawned
Process
If this process
fails, the JDBC Server executable could be corrupt, have incorrect
permissions, be missing, or be incompatible to the server operating
system (installed components for incorrect platform). The user can
log on to the server and manually verify the server installation
files.
Step 9. Attempting to Connect to the Specified
Database
If this step fails,
the client should receive an ALLBASE/SQL error message through the
java.sql.SQLException that is shown. Common causes of this failing are
incorrect database name or a corrupt database. Make sure the case-sensitivity
of the database name is also checked.
If all the preceding steps are successful, the Driver Manager
will return a connection to the database.
