Database using SQLiteOpenHelper Class accessing in main activity

I need to Preload some data in a sqlite database.I tried using Insert query.But it is inserting data everytime I open app.My searches made me understand SQLiteOpenHelper is the best option.But I am a beginner and I have no idea about SQLiteOpenHelper.I dont know how to implement it.I wrote this code.But how to access this database in my main activity.java

DataBaseHelper.java

public class DataBaseHandler extends SQLiteOpenHelper{

   public static final String DATABASE_NAME = "products.db";
   public static final String CONTACTS_TABLE_NAME = "product";
   public static final String CONTACTS_COLUMN_ID = "pid";
   public static final String CONTACTS_COLUMN_NAME = "pname";
   public static final String CONTACTS_COLUMN_EMAIL = "pspec";
   public static final String CONTACTS_COLUMN_STREET = "pprice";
   public static final String CONTACTS_COLUMN_CITY = "pfeature";
   public static final String CONTACTS_COLUMN_PHONE = "pimage";

public DataBaseHandler(Context context, String name, CursorFactory factory,
        int version) {
    super(context, name, factory, version);
    // TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub
    db.execSQL("CREATE TABLE IF NOT EXISTS product(pimage BLOB,pid INTEGER PRIMARY KEY,pname TEXT,pprice NUMERIC,pspec TEXT,pfeature TEXT)");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Candle stick 3',4000,'Solar garden / pathway light,Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA ,Material:Stainless steel ,WaterProof and safe ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Candle stick 4',4500,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Candle stick 5',3500,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Candle stick 6',6000,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('lawn Delight',8800,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('SGLC10',4500,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Senson',4500,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
    db.execSQL("INSERT INTO product(pname,pprice,pspec) VALUES('Thejus',7500,'Solar garden / pathway light, Solar Panel:1pc crystal silicon solar cell, Battery:1pc 1.2V Ni-MH/Ni-CD AA battery 600MA, Material:Stainless steel, WaterProof and safe IP44 ')");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub

}

}

Product_display.java

public class product_display extends Activity {

SQLiteDatabase db;

ListView prd_list;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.product_disply);
    prd_list = (ListView) findViewById(R.id.list);



     Intent in=getIntent();
     Bundle bundle=in.getExtras();
     final String list=bundle.getString("key");

    db = product_display.this.openOrCreateDatabase("products", MODE_PRIVATE, null);


    Cursor cr = db.rawQuery("SELECT * FROM product", null);
    final String[] pname = new String[cr.getCount()];
    String[] price = new String[cr.getCount()];

    int i = 0;
    while(cr.moveToNext())
    {
        String name = cr.getString(cr.getColumnIndex("pname"));
        String prprice = cr.getString(cr.getColumnIndex("pprice"));

        pname[i] = name;
        price[i] = prprice;
        i++;
    }

    ListAdapter adapter = new com.example.login_signup.ListAdapter(this, pname, price);
    prd_list.setAdapter(adapter);

    prd_list.setOnItemClickListener(new OnItemClickListener() {

        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            String nme = pname[arg2];   

            Bundle bun = new Bundle();
            bun.putString("key",list);
            Bundle bn = new Bundle();
            bn.putString("name",nme);
            Intent in = new Intent(product_display.this, Product_Details.class);
            in.putExtras(bun);
            in.putExtras(bn);
            startActivity(in);
            }

    });



}

}