Insert,Update,Delete in Android with Sqlite

MainActivity.java

package com.example.dml;
 import java.util.Locale;
 import android.app.Activity;
 import android.content.ContentValues;
 import android.content.Intent;
 import android.database.sqlite.SQLiteDatabase;
 import android.os.Bundle;
import android.view.View;
 import android.widget.Button;
 import android.widget.Toast;
 public class MainActivity extends Activity {
private SQLiteDatabase db;
 Button up;
 private String table_name="StudentInfo";
private String database_name="Test.db";
 private Object Button;
public static final String KEY_ROWID = "sid";
 public static final String KEY_NAME = "name";
public static final String KEY_AGE = "age";
 public static final String KEY_COURSE = "course";
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
 db = openOrCreateDatabase(database_name , SQLiteDatabase.CREATE_IF_NECESSARY, null);
 db.setVersion(1);
 db.setLocale(Locale.getDefault());
 db.setLockingEnabled(true);
// creating table in database
db.execSQL("CREATE TABLE IF NOT EXISTS "+table_name+" " + "( sid INTEGER PRIMARY KEY AUTOINCREMENT," + " name TEXT," + " age INTEGER," + " course TEXT ); ");
 }
public void onClick(View v) {
switch(v.getId()) {
 case R.id.btnInsert
: Insert("Rohit", "19", "BBA");
break;
 case R.id.btnUpdat:
 Update(1, "Rohit", "20", "BCA");
 break;
 case R.id.btnDelete:
Delete(1);
break;
} }
 public void Insert(String name, String age, String course)
{
 ContentValues data=createContentValues(name, age, course);
 db.insert(table_name, null, data);
 Toast.makeText(this, "Record Inserted", Toast.LENGTH_SHORT).show();
 }
// updating record in the database
 public void Update(int sid, String name, String age, String course)
 {
ContentValues updateValues = createContentValues(name, age, course);
db.update(table_name, updateValues, KEY_ROWID+"="+sid, null);
 Toast.makeText(this, "Record Updated", Toast.LENGTH_SHORT).show();
 }
// deleting record rom the database
public void Delete(int sid)
{
 db.delete(table_name, KEY_ROWID+"="+sid, null);
 Toast.makeText(this, "Record Deleted", Toast.LENGTH_SHORT).show();
 }
// return a content of the database
 private ContentValues createContentValues(String name, String age, String course)
{
ContentValues values = new ContentValues();
values.put(KEY_NAME, name);
 values.put(KEY_AGE, age);
 values.put(KEY_COURSE, course);
 return values;
 } }

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

 <Button android:id="@+id/btnInsert"

              android:text="Insert"

              android:layout_width="wrap_content"

              android:layout_height="wrap_content"

              android:onClick="onClick"/>
 <Button
        android:id="@+id/btnDelete"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/btnInsert"
        android:layout_below="@+id/btnInsert"
        android:layout_marginLeft="24dp"
        android:layout_marginTop="107dp"
        android:onClick="onClick"
        android:text="Delete" />


 <Button
        android:id="@+id/btnUpdate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/btnInsert"
        android:layout_marginLeft="57dp"
        android:layout_toRightOf="@+id/btnDelete"
        android:onClick=""
        android:text="Update" />

</RelativeLayout>