Client application to write our logic. Life cycle of POJO class. HQL Command to retrieve complete object. HQL Command to retrieve partial object. Example on selecting complete object. Example on selecting partial object with single column. Example on selecting partial object with more than one column. Example for deleting the object using HQL. Example for updating the object using HQL.

By using JDBC-API , we can write a java program to connect to any database in this world without changing the code. Sun MicroSystem was released JDBC API, this API consists set of classes and interfaces. The JDBC related classes and interfaces are available in packages are. The most important interface names of JDBC is. The most important class names of JDBC is.

JNDI API is used to communicate with directory server. Similar to the Database server, directory server is used to store the data. As part of the directory server the data will be store in the form of objects. We can choose directory server if insertion operations are very less and select operations are more number of times. We can store the data into database fast reader than database server. As part of directory server we can store very small amount of data.