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Question 16 :

How do I use multibyte character sets with WebLogic jDriver for Informix?

Answer :

Currently, multibyte character sets are not supported for the WebLogic jDriver for Informix driver.


Question 17 :

How do I connect to an SQL Server instance that is running on a machine with multiple instances of SQL Server 2000?

Answer :

Each instance of MS SQL Server must be listening on a different port. So, you can use the port number in the properties that you pass to the getConnection() method or, in case of connection pools, you can specify the port property in the following properties:
server=machineName
port=instancePort

To find the port number where each MS SQL Server instance is running, run the server network utility (in the Microsoft SQL Server program group), select the server instance, select TCP/IP, and click the properties button.


Question 18 :

Why does FOR UPDATE in Oracle 8 cause an ORA-01002 error?

Answer :

The Oracle 8 server generates an ORA-01002:fetch out of sequence error message when you use a FOR UPDATE statement with AUTOCOMMIT turned on (which is the default state when using JDBC). This is known to happen on Oracle 8.0 and 8.1 on Solaris and on Oracle 8.1 on Windows NT. If you turn AUTOCOMMIT off, you will not receive this error. Because this problem is due to a change in the Oracle 8 server, you should contact Oracle support for more information.


Question 19 :

What causes an OCIW32.dll error?

Answer :

You may receive the following error message when using your JDBC driver for Oracle: "The ordinal 40 could not be loaded in the dynamic link library OCIW32.dll." This problem is caused by an out-of-date version of OCIW32.DLL in your system directory. Some programs install this file in the system directory in order to run. If you remove this file from the system directory you should no longer receive this error.


Question 20 :

What transaction isolation levels does the WebLogic jDriver for Oracle support?

Answer :

Your servlet application may use Oracle Thin Drivers to access a database that includes BLOB fields. If you install and try to use WebLogic jDriver for Oracle and the same code fails and produces an exception similar to the following:

com.roguewave.jdbtools.v2_0.LoginFailureException:
TRANSACTION_READ_UNCOMMITTED isolation level not allowed
The Stack Trace:
com.roguewave.jdbtools.v2_0.LoginFailureException:
TRANSACTION_READ_UNCOMMITTED isolation level not allowed
at
com.roguewave.jdbtools.v2_0.jdbc.JDBCServer.createConnection
(JDBCServer.java :46)
at com.roguewave.jdbtools.v2_0.ConnectionPool.getConnection_
(ConnectionPool.jav a:412)
at com.roguewave.jdbtools.v2_0.ConnectionPool.getConnection
(ConnectionPool.java :109)

Setting the Isolation_level to 1 in the code that calls the RogueWave JDBCServer class works with the Oracle thin driver but fails with WebLogic jDriver for Oracle.

WebLogic jDriver for Oracle supports the following transaction isolation levels:

SET TRANSACTION ISOLATION LEVEL READ COMMITTED
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE

According to the Oracle documentation, the Oracle DBMS only supports these two isolation levels. Unlike other JDBC drivers, WebLogic's drivers throw an exception if you try to use an isolation level that is unsupported. Some drivers silently ignore attempts to set an unsupported isolation level. WebLogic suggests testing whether the Oracle thin driver is not just ignoring settings for unsupported isolation events.