sqlite database image stored success but update not working.Am store image in blob type

Am stored image in sqlite database.i stored successfully after that am retrieve image it also working fine.but update the image not work.i cant find the problem.no error shows after update i retrieve image but noting show in image view

db.execSQL("CREATE TABLE if not exists producttable1(id INTEGER PRIMARY KEY AUTOINCREMENT,"
        + "subid TEXT,"
        + "submenue  TEXT,"
        + "submenut TEXT,"
        + "status TEXT,"
        + "submenuh TEXT,"
        + "rate TEXT,"
        +"photo BLOB,"      
        + "imgstat TEXT,"
        + "stackstat TEXT," + "noitem TEXT)");
public void addsubmenu(Model md) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("subid", md.subid);
contentValues.put("submenue", md.smenue);
contentValues.put("submenut", md.smenut);
contentValues.put("submenuh", md.smenuh);
contentValues.put("rate", md.rate);
contentValues.put("noitem", md.noitem);
contentValues.put("status", md.status);
contentValues.put("stackstat", md.stackstat);
contentValues.put("photo",md.photo);
contentValues.put("imgstat",md.imgstat);
db.insert("PRODUCTTABLE1", null, contentValues);
db.close();
}
     public void updateitem(Model productList) {
SQLiteDatabase db = this.getWritableDatabase();
//byte[] byteImage2 = null;
ContentValues contentValues = new ContentValues();
contentValues.put("id", productList.id);
contentValues.put("smenue", productList.smenue);
contentValues.put("smenut", productList.smenut);
contentValues.put("smenuh", productList.smenuh);
contentValues.put("rate", productList.rate);
contentValues.put("noitem", productList.noitem);
contentValues.put("photo",productList.photo);
contentValues.put("imgstat",productList.imgstat);   









db.execSQL("update producttable1 set submenue='" + productList.smenue
            + "',submenut='" + productList.smenut + "',submenuh='"
            + productList.smenuh + "',photo='"+productList.photo+"',imgstat='"+productList.imgstat+"',rate='" + productList.rate
            + "',noitem='" + productList.noitem + "' where id='"
            + productList.id + "'");    


db.close();

}