how to write update query and insert query for fileupload in asp.net?

    try
    {
        string[] validFileTypes={"bmp","gif","png","jpg","jpeg","JPG","BMP","GIF","PNG","JPEG"};
    string ext = System.IO.Path.GetExtension(FileUpload1.PostedFile.FileName);
    bool isValidFile = false;
    for (int i = 0; i < validFileTypes.Length; i++)
    {
        if (ext == "." + validFileTypes[i] )
        {
            isValidFile = true;
            break;
        }
    }
    if (!isValidFile)
    {
        Response.Write("<script language='javascript'>alert('Invailed File')</script>");
    }
    else if(Image2.ImageUrl==null)
    {
        //delete();
        Byte[] bytes = null;
        if (FileUpload1.HasFile)
        {

            string filename = FileUpload1.PostedFile.FileName;
            string filePath = Path.GetFileName(filename);
            Stream fs = FileUpload1.PostedFile.InputStream;
            BinaryReader br = new BinaryReader(fs);
            bytes = br.ReadBytes((Int32)fs.Length);

        }
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con"].ConnectionString);
        SqlCommand command = new SqlCommand(
         "INSERT INTO " + U_name.Text + " (U_name, Image) " +
         "Values(@U_name, @Image)", con);
        command.Parameters.Add("@U_name",
        SqlDbType.NVarChar, 20).Value = U_name.Text.Trim();
        command.Parameters.Add("@Image",
        SqlDbType.Binary).Value = bytes;
        con.Open();
        command.ExecuteNonQuery();
        Label2.ForeColor = System.Drawing.Color.Green;
        Label2.Text = "Successfully";
    }
        else
    {

        Byte[] bytes = null;
        if (FileUpload1.HasFile)
        {
            string filename = FileUpload1.PostedFile.FileName;
            string filePath = Path.GetFileName(filename);
            Stream fs = FileUpload1.PostedFile.InputStream;
            BinaryReader br = new BinaryReader(fs);
            bytes = br.ReadBytes((Int32)fs.Length);
        }
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con"].ConnectionString);
        SqlCommand command = new SqlCommand("UPDATE " + U_name.Text + " SET Image=@Image " +"", con);
        command.Parameters.Add("@Image",SqlDbType.Binary).Value = bytes;
        con.Open();
        command.ExecuteNonQuery();
        Label2.ForeColor = System.Drawing.Color.Green;
        Label2.Text = "UPDATE Successfully";
    }

}