JDBC (Java Database Connectivity) Code

JDBC (Java Databse Connectivity)

package :  java.sql  (API)

How to Connect DB with Java?

1- Create Data Soure Name (DSN)

JavaApplication -->JDBc-->DSN-->Driver(ODBC)-->Database

odbcad32

2- Java Application Steps
   i) Load Driver

    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

   ii) Establish Connection with db

   Connection con=
DriverManager.createConnection("jdbc:odbc:Lahore");
        con.setAutoCommit(false);
  iii)create Statement Object (for SQL)

     Statement stmt= con.createStatement();


  iv) run Query
 String qry="insert into user values("Hafiz","123")"

     stmt.executeUpdate(qry);

 iv) Commit Transaction
     con.commit();

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Example: Establish Connection
import java.sql.*;
import java.sql.*;
class MyDb{
private Connection con;
MyDb() {
 try {
   Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
   con=DriverManager.getConnection("jdbc:odbc:Lahore");
   System.out.print("Connection Established ....");
  }catch (Exception e ) { System.out.print(e);}
}


}

class Test{
public static void main(String o[]){
MyDb db=new MyDb();

}
}
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Example: insert row
import java.sql.*;
import java.sql.*;
class MyDb{
private Connection con;
private Statement stmt;
MyDb() {
 try {
   Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
   con=DriverManager.getConnection("jdbc:odbc:Lahore");
   stmt=con.createStatement();
   con.setAutoCommit(false);
   System.out.print("Connection Established ....");
  }catch (Exception e ) { System.out.print(e);}
}
void insertRow(String username,String password){
String qry="insert into user values('"+username+"','"+password+"')";
   try{
    stmt.executeUpdate(qry);
    con.commit();
    System.out.print("Successfully Saved");
   }catch (Exception e ) { System.out.print(e);}

}


}

class Test{
public static void main(String o[]){
MyDb db=new MyDb();
String username=o[0];
String password=o[1];
db.insertRow(username, password);
}
}

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Example: Retrive  rows

import java.sql.*;
import java.sql.*;
class MyDb{
private Connection con;
private Statement stmt;
private ResultSet rs;
MyDb() {
 try {
   Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
   con=DriverManager.getConnection("jdbc:odbc:Lahore");
   stmt=con.createStatement();
   con.setAutoCommit(false);
   System.out.print("Connection Established ....");
  }catch (Exception e ) { System.out.print(e);}
}
void insertRow(String username,String password){
String qry="insert into user values('"+username+"','"+password+"')";
   try{
    stmt.executeUpdate(qry);
    con.commit();
    System.out.print("Successfully Saved");
   }catch (Exception e ) { System.out.print(e);}

}
void retrieveRow(String qry){
     try {
        rs=stmt.executeQuery(qry);
        while (rs.next()){
System.out.println(rs.getString("username") + "\t"+rs.getString("password"));

        }

     }catch (Exception e ) { System.out.print(e);}


}

}

class Test{
public static void main(String o[]){
MyDb db=new MyDb();
String qry=o[0];
db.retrieveRow(qry);
}
}

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