24-01-25
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Q)Dedevelop a JDBC Applicatimport java.sql.*;//making JDBC API available to the program
class  UpdateApplication{
	public static void main(String[] args)throws SQLException{
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/ashokitdb","root","ashokit");
		Statement statement=connection.createStatement();
		int re=statement.executeUpdate("UPDATE ACCOUNT SET BALANCE=BALANCE+5000");
		System.out.println(re+" rows effected");
		statement.close();
		connection.close();
	}
}
ion that increases the balance of all the accounts
by Rs.5000.
UPDATE ACCOUNT SET BALANCE=BALANCE+5000
import java.sql.*;//making JDBC API available to the program
class  UpdateApplication{
	public static void main(String[] args)throws SQLException{
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/ashokitdb","root","ashokit");
		Statement statement=connection.createStatement();
		int re=statement.executeUpdate("UPDATE ACCOUNT SET BALANCE=BALANCE+5000");
		System.out.println(re+" rows effected");
		statement.close();
		connection.close();
	}
}
Q)Develop a Java application to delete a specified  account form the database table.
//DeleteAccount.java
import java.sql.*;//making JDBC API available to the program
import java.util.Scanner;
class  DeleteApplication{
	public static void main(String[] args)throws SQLException{
		Scanner scanner=new Scanner(System.in);
		System.out.println("Enter the A/NO");
		int n=scanner.nextInt();
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/ashokitdb","root","ashokit");
		Statement statement=connection.createStatement();
		int de=statement.executeUpdate("DELETE FROM ACCOUNT WHERE ACCNO="+n);
		if(de==0){
			System.out.println("Account doesn't exist");
		}
		else{
			System.out.println("deleted sucessfully");
		}
		
	       statement.close();
		connection.close();
		scanner.close();
	}
}
Q)How to read data from the database?
    =>By submitting SELECT statement to the DBMS, data is retrieved from the database.
    =>by using executeQuery() method on the statement object,
    SELECT STATEMENT IS submitted to the DBMS.

    ResultSet resultset=statement.executeQuery("SELECT ...");

Q)Explain about java.sql.ResultSet?
=>Object oriented representation of database records is nothing but ResultSet object.
=>ResultSet has the following structure.
DIAGRAM

=>When the ResultSet is open, a logical pointer known as cursor points to
the ZERO recrod area.

=>When the cursor is pointing to ZERO record area OR no record area,we should
not retireve the column values

=>to move the cursor we use "next()" method of ResultSet object.

=>next() method does two things.
       1)It moves the cursor by one record (area) in forward direction
       2)It returns true if record exits otherwise false.

=>to read the column values, getXXX() methods of the ResultSet are used.
=>These methods take column number of the ResultSet record as argument
and returns column value.
For eg.
                         int ano=resultset.getInt(1)
			 String name=resultset.getString(2);
			 double balance=resultset.getDouble(3);
Q)Develop a JDBC application to retrieve all the accounts from the database
and display their details.
import java.sql.*;//making JDBC API available to the program
class  ReadApplication{
	public static void main(String[] args)throws SQLException{
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/ashokitdb","root","ashokit");
		Statement statement=connection.createStatement();
		ResultSet resultset=statement.executeQuery("SELECT * FROM ACCOUNT");
		System.out.println("ACCNO  NAME  BALANCE");
                while(resultset.next()){
                      System.out.println(resultset.getInt(1)+"  "+resultset.getString(2)+" "+resultset.getDouble(3));
		}
		resultset.close();
		statement.close();
		connection.close();
	}
}