Monday, May 24, 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();
}
}
}

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