1) Download the instant client for OCI which is platform specific from the below link
a. Download the appropriate Instant Client packages for your platform. All installations REQUIRE the Basic package.
b. Unzip the packages into a single directory such as “instantclient”.
c. Set the library loading path in your environment to the directory in Step 2 (“instantclient”).
– On many UNIX platforms, LD_LIBRARY_PATH is the appropriate environment variable. On Windows, PATH should be used.
2) Give the classpath in the pre classpath in the startup script up to ojdbc14.jar present inside the above zip file
In windows as below:-
3) Open a Weblogic admin console
4) Go to the created datasource under the connection pool settings and change the class name as oracle.jdbc.OracleDriver and url as jdbc:oracle:oci:@ DATABASE SID
5) Test the datasource.
6) Save settings.