In weblogic5.1 for the database connection we are fetching it from the ConnectionPool.What type of driver is it(among 4 types).How to find out.
The four driver types says what type of implementation the driver is. As an application programmer, you don't have to care about the driver type. All drivers you get from the JNDI namespace are represented as an object implementing the DataSource interface.
I presume you are using jDrivers of WebLogic. The jDrivers of WebLogic are Type-2 in case of Oracle, DB2 and Type-4 in case of MS SQL and Informix.
To use Type-2 drivers you will have to give the database client libraries in the PATH or LD_LIBRARY_PATH(unix). For Type-4 drivers it is not required but you will have to include the driver in the CLASSPATH. This is the only way Type-2 and Type-4 are differentiated.
Type-3 will be always used in the App Server when you are accessing the connections pools. Hence if you are accessing the database via connection pool from a Servlet, EJB, start-up class... etc you will be using a combination of Type-3 and Type (2 or 4) drivers.
Type 1 is odbc-jdbc bridge which is very rarely used...