JDBC FAQ Part9

18: If we use selection group SQL query to executeUpdate() ,what happened?

• If we use selection group sql query as a parameter to executeUpdate(…) then JVM will send that sql query to the DBE, DBE will fetch the data and send  back to the java application here java application will store the fetched data in the form of ResultSet object. But executeUpdate() is expecting records  updated count value.

            Due to this contradiction JVM will rise an exception like java.lang.SQLException.

If we handle the above exception properly then we will get ResultSet abject and we will get the data from Database

import java.sql.*;
class Test
{
public static void main(String[] args)
{
            Statement st=null;
            try
            {    
                        Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);

                     Connection con = DriverMadoeer.getConnection(“jdbc:odbc:doe”,”system”,”jhon”);

                        st = con.createStatement();
boolean b = st.executeUpdate(“select * from emp1”);
            }
            catch(Exception e)
            {
                        ResultSet rs=st.getResultSet();
            System.out.println(“ENO      ENAME      ESAL      EADDR”);
            System.out.println(“********************************”);
            while(rs.next())
            {
                        System.out.println(rs.getInt(1)+””+rs.getString(2)+”   ”+rs.getFloat(3)+”              ”+rs.getString(4));
            }

                        e.printStackTrace();
            }

}

19: If we use updatation group SQL query to executeQuery() ,what happened?

• If we use updation group sql query as a parameter to executeQuery() then JVM will send that sql query to the DBE, DBE will perform updations on the database and send back records updated count value to the java application. But here executeQuery() is expecting ResultSet object reference.

            Due to this contradiction JVM will rise an exception like java.lang.SQLException.
      
import java.sql.*;
class Test
{
public static void main(String[] args)
{
            Statement st=null;
            try
            {    
                        Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);

                     DriverMadoeer.getConnection(“jdbc:odbc:doe”,”system”,”jhon”);

                        st = con.createStatement();
  boolean b = st.executeQuery(“update  emp1 set esal=esal+1000 where         esal <10000”);
            }
            catch(Exception e)
            {
                        int count=st.getUpdateCount();
                        System.out.println(count);

                        e.printStackTrace();
            }

}