Introduction to JDBC(Java Database Connectivity)

What is JDBC?

JDBC stands for Java Database Connectivity, which is a standard Java API for database-independent connectivity between the Java programming language and a wide range of databases.

The JDBC library includes APIs for each of the tasks commonly associated with database usage:

•  Making a connection to a database
•  Creating SQL or MySQL statements
•  Executing that SQL or MySQL queries in the database
•  Viewing & Modifying the resulting records

JDBC Environment setup

Before connecting your code to the database,make sure that you have done following setup:

1. Core JAVA Installation
2. Any Database Installation

Apart from the above you need to setup a database which you would use for your project.

Creating JDBC Application:

JDBC application creation can be broadly divided into some easy and small steps.

Step 1: Importing required packages

import java.sql.*;

Step 2: Register JDBC driver

It basically initializes a driver so that you can open a communication channel with the database.Following is the code snippet to achieve this:

Class.forName("org.postgresql.Driver"); //I am using Postgresql database.

Step 3: Open a Connection

This step requires a method i.e. DriverManager.getConnection() method to be create a Connection object which represents a physical connection with the database.

con = DriverManager.getConnection(DB_URL,USER,PASS);

Step 4 : Executing a query

This step will help you to build a statement that will build and submit as a SQL statement to the database.

stmt = conn.createStatement();
String sql;
sql = "SELECT id, first, last, age FROM Students";
ResultSet rs = stmt.executeQuery(sql);

Step 5: Extracting data from result set

This step will help you in fetching data from database.You can use the appropriate Result.getXYZ()

while(rs.next())
{ //Retrieve by column name
int id = rs.getInt("id");
int age = rs.getInt("age");
//Displaying values
System.out.println("ID:"+ id);
System.out.println(",Age :"+ age);

Step 6: Closing the environment

Its a good habit to close all database resources before program exits.

rs.close();
stmt.close();
con.close();

This post was just a simple introduction about JDBC,in the next post we will discuss about the new and powerful database i.e. PostgreSQL.