Friday, March 25, 2011


Since entities form the heart of the JPA, they have some unique characteristics like persistability, identity and transactionability. The property of persistability deals with the storing and retrieving of entity from and to a persistent medium like database. Identity property is usually used to identity one unique entity among multiple entities (or multiple entity instances) in a database. All the CRUD operations (Create, Update and Delete) for entity objects will occur within a transactional context and it is one of the major characteristic for an entity object as the real state of an entity depends whether a transaction completes (commits/fails) or not.


import  java.sql.*;

public class AllTableName{
public static void main(String[] args) {
System.out.println( "Listing all table name in Database!" );
Connection con = null ;
String url = "jdbc:mysql://localhost:3306/" ;
String db = "jdbctutorial" ;
String driver = "com.mysql.jdbc.Driver" ;
String user = "root" ;
String pass = "root" ;
try {
con = DriverManager.getConnection(url+db, user, pass);
try {
DatabaseMetaData dbm = con.getMetaData();
String[] types = { "TABLE" };
ResultSet rs = dbm.getTables(null,null, "%" ,types);
System.out.println( "Table name:" );
while ({
String table = rs.getString( "TABLE_NAME" );
catch (SQLException s){
System.out.println( "No any table in the database" );
catch (Exception e){

Above program retrieves the names of all tables present in the database and then displays on the console.

Advantages of JDBC

  • Clean and easily for small programs
  • JDBC provides good performance with large amount of data
  • Small JDBC programs can be developed very easily
  • Very good for small applications

Disadvantages of JDBC

  • JDBC is not easily if it is used in large projects. There is a big programming overhead.
  • Programmer must hardcode the Transactions and concurrency code in the application.
  • Handling the JDBC connections and properly closing the connection is also a big issue. Properly closing the connection is must.
  • JDBC is not good for big applications


ORM stands for Object Relational Mapping, is another technology to access the data databases. Here business object is directly mapped to the database tables with the help of ORM framework.

ere are the benefits of ORM technology

  • No need to deal with the SQL Queries to save and retrieve the data
  • Simple configuration
  • Standardized API to persist the business objects
  • Fast development of application
  • Concurrency support
  • Excellent cashing support for better performance of the application
  • Injected transaction management
  • Configurable logging
  • Easy to learn and use

Disadvantages of ORM

  • Slow performance in case of large batch updates
  • Little slower than JDBC 

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