365edu Online Tutorials

Thursday, April 29, 2010

Retrieving All Rows from a Database Table

Here, you will learn how to retrieve all rows from a database table. You know that table contains the data in rows and columns format. If you want to access the data from a table then you need to use some APIs and methods. See brief descriptions for retrieving all rows from a database table as below:

Description of program:
Program establishes the connection between MySQL database and java file so that the we can retrieve all data from a specific database table. If any exception occurs then shows a message "SQL code does not execute.".

Description of code:

executeQuery(String sql):
This method executes the SQL statement and returns a single ResultSet object. It takes string type parameter for executing the SQL statement.

SELECT * FROM table_name:
Above code retrieves all data from specific database table.

getInt(String column_name):
This method is of java.sql.ResultSet interface that takes string type parameter and returns an integer type values.

getString(String column_name):
This method is same as getInt() method but it returns the string type values.

Here is the code of program:

import java.sql.*;



public class GetAllRows{

public static void main(String[] args) {

System.out.println("Getting All Rows from a table!");

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{

Class.forName(driver).newInstance();

con = DriverManager.getConnection(url+db, user, pass);

try{

Statement st = con.createStatement();

ResultSet res = st.executeQuery("SELECT * FROM employee6");

System.out.println("Emp_code: " + "\t" + "Emp_name: ");

while (res.next()) {

int i = res.getInt("Emp_code");

String s = res.getString("Emp_name");

System.out.println(i + "\t\t" + s);

}

con.close();

}

catch (SQLException s){

System.out.println("SQL code does not execute.");

}

}

catch (Exception e){

e.printStackTrace();

}

}

}
 
Output of Program