i've tried the following code in to retrieve data from db. insertion is working fine. but retrieval is the pblm.

My code for an attendance database

public class Main2Activity extends AppCompatActivity {

SQLiteDatabase db;
TextView tv;
EditText e1;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    MainActivity obj=new MainActivity();
    tv=(TextView)findViewById(R.id.textView1);
    e1=(EditText)findViewById(R.id.edText1);
    db= openOrCreateDatabase("Mydb", MODE_PRIVATE, null);
    db.execSQL("create table if not exists mytable1(id varchar,val varchar )");
    db.execSQL("create table if not exists mytable2(id varchar,val varchar)");
}
public void insert(View v)
{
    String name=e1.getText().toString();
    String option="present";
    // String sur_name=et1.getText().toString();
    e1.setText("");
    //et1.setText("");
    //insert data into able
    db.execSQL("insert into mytable1 values('"+name+"','"+option+"')");
    //display Toast
    Toast.makeText(this, "value inserted successfully.", Toast.LENGTH_LONG).show();
}
public void insert2(View v)
{
    String name=e1.getText().toString();
    String option2="absent";
    //String sur_name=et1.getText().toString();
    e1.setText("");
    //et2.setText("");
    //insert data into able
    db.execSQL("insert into mytable2 values('"+name+"','"+option2+"')");
    //display Toast
    Toast.makeText(this, "values inserted successfully.", Toast.LENGTH_LONG).show();
}
public void display(View v)
{
    //use cursor to keep all data
    //cursor can keep data of any data type
    Cursor c1=db.rawQuery("select * from mytable1", null);
    tv.setText("");
    //move cursor to first position
    c1.moveToFirst();
    //fetch all data one by one
    do
    {
        //we can use c.getString(0) here
        //or we can get data using column index
        String name=c1.getString(c1.getColumnIndex("id"));
        String surname=c1.getString(1);
        //display on text view
        tv.append("Name:"+name+" and SurName:"+surname+"\n");
        //move next position until end of the data
    }while(c1.moveToNext());

}

} Not able to find out errors in this code! even tried changing datatype of val to integer autoincrement. doesnt work