Android Studio Inserting Data in onCreate and Deleting Data in onDestroy

I use an insert query in onCreate and I want to delete all that data in onDestroy but I cant make it work, everytime I start the application the data is doubled. It seems that onDestroy is not working.

checkout my codes

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_student_view);
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    myDbHelper = new DatabaseHelper(this, DATABASE_NAME, null,
            DATABASE_VERSION);

    sqlHandler = new SQLHandler(this);
    mDb = myDbHelper.getWritableDatabase();
    String query = "INSERT INTO scholar_table(Name,Top,Continent,Region,Location,Introduction,Alumni) " +
            "values ('Wesleyan University Philippines','290','Luzon','Region 3','Nueva Ecija','WUP Intro','WUP Alumni')";
    sqlHandler.executeQuery(query);

 @Override
    public void onDestroy(){
        super.onDestroy();
        sqlHandler = new SQLHandler(this);
        mDb = myDbHelper.getWritableDatabase();
        String query = "DELETE * FROM scholar_table";
        sqlHandler.executeQuery(query);
        finish();
    }