need your help, i am a new programmer, want to learn something from you

byte[] bytes = File.ReadAllBytes(@"D:\Temp\MyFile.doc");

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand com = new SqlCommand("INSERT INTO myTable (myFileDataColumn) VALUES (@DATA)", con))
        {
        com.Parameters.AddWithValue("@DATA", bytes);
        com.ExecuteNonQuery();
        }
    }

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand com = new SqlCommand("SELECT myFileDataColumn FROM myTable", con))
        {
        using (SqlDataReader reader = com.ExecuteReader())
            {
            while (reader.Read())
                {
                byte[] bytes = (byte() reader["myFileDataColumn "];
                File.WriteAllBytes(@"D:\Temp\MyFileBackAgain.doc", bytes);
                }
            }
        }
    }