Соединение с базой данных вручную

string CommandText = "select * from Туристы;";
            string ConnectString =
                @"Data Source = .\SQLEXPRESS;" +
                @"AttachDBFilename = C:\Program Files\Microsoft SQL Server Compact Edition\v3.5\Desktop\SQL_Test_1.mdf;" + 
                "Integrated Security = true;" +
                "Connect Timeout = 30;" +
                "User Instance = true";
            SqlConnection conn = new SqlConnection(ConnectString);
            conn.Open();
            SqlCommand command = conn.CreateCommand();
            command.CommandText = CommandText;
            SqlDataAdapter dataAdapter = new SqlDataAdapter();
            dataAdapter.SelectCommand = command;
            DataSet ds = new DataSet();
            dataAdapter.Fill(ds, "Туристы");
            dataGridView1.DataSource = ds.Tables["Туристы"].DefaultView;
            conn.Close();

string CommandText = "select * from Туристы;";

            string ConnectString =
                "Data Source = Boboka;" +
               "Initial Catalog = SQL_Test_1;" +
              "Integrated Security = SSPI;";

public SqlCeConnection cn = new SqlCeConnection(@"Data Source=|DataDirectory|\database.sdf");
 
.............
cn.Open(); //Открыть базу
.............

SqlCeCommand login = new SqlCeCommand("SELECT LOGIN FROM tb_auth WHERE LOGIN ='"+textBox1.Text+"'",cn);
            SqlCeCommand pass = new SqlCeCommand("SELECT PASS FROM tb_auth WHERE LOGIN = '"+textBox1.Text+"' ",cn);
 
 
            if (textBox1.Text == login.ExecuteScalar().ToString() && textBox2.Text == pass.ExecuteScalar().ToString())
            {
 
                SqlCeCommand fio = new SqlCeCommand("SELECT FIO FROM tb_auth WHERE LOGIN = '" + textBox1.Text + "'", cn);
             MessageBox.Show("Приветствуем Вас, " + fio.ExecuteScalar().ToString() + " !");