JDBC

What is JDBC JDBC is an acronym for –Java Data Base Connectivity. It allows java/jsp program to connect to any database

How to use JDBC Step1: First make a database Step2: Create tables Step3: Create data source

JDBC library in Java To use JDBC in java, you need to know about –Connection –Statement –ResultSet –DriverManager All these classes are provided in pacakkage java.sql.*.

Steps to use JDBC in Java Initialize variables Register or Load Driver Open a Connection Execute Sql Statement Close the Connection

Initialize Variables You need following variables Connection con; Statement stmt; Initialize variable to value null Connection con = null; Statement stmt = null;

Load Driver To load driver you need to use Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); sun.jdbc.odbc.JdbcOdbcDriver is the name of driver. Class.forName() function loads the driver in memory.

Create Connection After loading driver, you need to create a connection Create connection means, you need to connect your java program with the database. To connect to a database you must configure the DSN first DSN is an acronym for Data Source Name

What is DSN DSN is an acronym for Data Source Name DSN act as an interface between your java application and Database To create DSN –Open Control Panel –Administrative Tools –ODBC

Create Connection Contd After loading driver and creating DSN, next step is to create a connection. To create a connection conn = DriverManager.getConnection("jdbc:odbc:cdb"); DriverManager class getConnection functions takes DSN as input argument And returns an object of type Connection

Create Statement After creating connection, you need to create statement Statement stmt = conn.createStatement(); conn is a connection object created in previous slide

Execute Query After connection is created successfully, you need to execute query There are 2 types of query –That gets record from database –That insert or update or delete record

Insert or update or delete record To insert record in database, use method executeUpdate of statement class. int i = stmt.executeUpdate("INSERT INTO personal VALUES('"+lname+"','"+fname+"','"+sex+"','"+salary+"','"+exp+"')"); This method takes as input “Insert” query statement. This method returns 1 (success) or 0 (failure). You can replace “Insert” query statemetn with update or delete query statement.

Get record from database To retrieve or get record from database executeQuery() method is used. ResultSet rs = stmt.executeQuery(“Select lname, fname from personal"); The method executeQuery() takes “select” statement as input. The method executeQuery() returns an object of type ResultSet.

Complete Program for Inserting a record in Database <% Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:odbc:cdb"); Statementstmt = conn.createStatement(); %>

Contd…. String lname = request.getParameter("fname"); String fname = request.getParameter("lname"); String sex = request.getParameter("sex"); String salary = request.getParameter("salary"); String exp = request.getParameter("experience");

Contd…. i = stmt.executeUpdate("INSERT INTO personal VALUES('"+lname+"','"+fname+"','"+sex+"','"+salary+"','"+e xp+"')"); if (i ==1) { System.out.println("success"); //response.sendRedirect("conjoint.html"); } else {System.out.println("There has been some problem in saving your personal information. Kindly fill the personal information again"); }

Complete Program for Retrieving records from query Connection conn = null; Statement stmt = null; ResultSet rs = null;

Contd…. Class.forName("sun.jdbc.odbc.JdbcOdbcD river"); conn = DriverManager.getConnection("jdbc:odbc: cdb"); stmt = conn.createStatement();

Contd…. rs = stmt.executeQuery("Select fname, lname from personal"); while(rs.next()) { System.out.println(rs.getString(1) + " " +rs.getString(2)); // rs.next(); } %>