ช่วยหน่อยครับ อธิบาย syntax และหลักการทำงานโค้ด web service นี้หน่อย

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.ComponentModel;
using System.Data.SqlClient;

// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// <System.Web.Script.Services.ScriptService()> _
[System.Web.Services.WebService(Namespace = "http://tempuri.org/")]
[System.Web.Services.WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ToolboxItem(false)]
public class getCustomerDetail : System.Web.Services.WebService
{

	[WebMethod()]
	public DataTable DetailCustomer(string strCusID)
	{
		SqlConnection objConn = new SqlConnection();
		SqlCommand objCmd = new SqlCommand();
		SqlDataAdapter dtAdapter = new SqlDataAdapter();

		DataSet ds = new DataSet();
		DataTable dt = null;
		string strConnString = null;
		StringBuilder strSQL = new StringBuilder();

		strConnString = "Server=localhost;UID=sa;PASSWORD=;database=mydatabase;Max Pool Size=400;Connect Timeout=600;";

		strSQL.Append(" SELECT * FROM customer ");
		strSQL.Append(" WHERE [CustomerID] = '" + strCusID + "' ");

		objConn.ConnectionString = strConnString;   
		var _with1 = objCmd;
		_with1.Connection = objConn;
		_with1.CommandText = strSQL.ToString();
		_with1.CommandType = CommandType.Text;
		dtAdapter.SelectCommand = objCmd;

		dtAdapter.Fill(ds);
		dt = ds.Tables[0];

		dtAdapter = null;
		objConn.Close();
		objConn = null;

		return dt;

	}

}