sqllite 的数据不知道怎么没了？

因为第一次用sqllite，用错的地方还请大家指出来，我下面我把关键的代码贴上来public static string dbConn2 = "Data Source =\\My Documents\\shop.db;Cache Size=2000;New=True;Compress=False;Synchronous=Full;UTF8Encoding=False;Version=3";        //打开SQLite数据库
        public static SQLiteConnection DBConn()
        {
            SQLiteConnection sqLiteConn = null;
            try
            {
                sqLiteConn = new SQLiteConnection(dbConn2);
                sqLiteConn.Open();
                return sqLiteConn;
            }
            catch (Exception e)
            {
                return null;
            }
        }
        //从SQL CE数据库获得数据集
        public static DataSet GetDataSet(string sql)
        {
            SQLiteConnection conn;
            SQLiteDataAdapter da;
            if (null == (conn = DBConn())) return null;
            da = new SQLiteDataAdapter(sql, conn);
            try
            {
                DataSet ds = new DataSet();
                da.Fill(ds);
                return ds;
            }
            catch(Exception e)
            {
                return null;
            }
            finally
            {
                if (null != conn) conn.Close();
            }
        }引用：
            string sql = "select * from shop where item_no='"+barcode+"'";
            DataSet ds = new DataSet();
            ds=initDB.GetDataSet(sql);
            string context = "";
            if (ds!=null)
            {
                if (ds.Tables[0].Rows.Count>0)
                {
                    context += "名称:" + ds.Tables[0].Rows[0][1];
                    context += "进价:" + ds.Tables[0].Rows[0][2];
                    context += "供应商:" + ds.Tables[0].Rows[0][3];
                    textBox2.Text = context;
                }
                else
                {                }
            }
            else
            {
                textBox2.Text = "数据查询失败";
            }
然后出现的情况就是no such table 没有这样的表，现在有的数据库也变了0节字，大家指点一下