Lambda表達式轉SQL語句類庫

/* 作者：道法自然 * 個人郵件：myyangbin@sina.cn* 2014-10-1*/Lambda表達式轉SQL語句類庫源碼下載：http://download.csdn.net/detail/xftyyyyb/8044085一、可以達到的功能本功能類庫主要提供給代碼中使用Lambda表達式，后需轉成SQL的條件語句這一需求。二、不能做的1、本類庫不能解析Linq語句；2、不能解析SQL中的Select部分；三、案例：1、以Northwind數據庫Customers表為例，為使問題簡單，僅用部分字段演示 /// <summary> /// 客戶管理 /// </summary> public class Customers { /// <summary> /// 客戶ID /// </summary> public string CustomerID { get; set; } /// <summary> /// 公司名稱 /// </summary> public string CompanyName { get; set; } /// <summary> /// 地址 /// </summary> public string Address { get; set; } }2、可能會有如下方法訪問數據庫 public static Customers Data_Fetch(string aiWhere, string aiOrderBy) { var cnstr = ConfigurationManager.ConnectionStrings["DemoConnectionString"].ConnectionString; Customers aiCustomers = new Customers(); StringBuilder aisd = new StringBuilder(); using (SqlConnection cn = new SqlConnection(cnstr)) { #region 數據訪問 #region 查詢SQL語句 aisd.Append(" SELECT "); aisd.Append(" CustomerID,CompanyName,Address "); aisd.Append(" FROM Customers "); aisd.Append(aiWhere); aisd.Append(aiOrderBy); #endregion cn.Open(); using (SqlCommand cmd = new SqlCommand(aisd.ToString(), cn)) { using (SqlDataReader myDataReader = cmd.ExecuteReader()) { if (myDataReader.HasRows) { myDataReader.Read(); aiCustomers = new Customers { #region 類賦值 CustomerID = (string)myDataReader["CustomerID"], CompanyName = (string)myDataReader["CompanyName"], Address = (string)myDataReader["Address"] #endregion }; } }; } #endregion } return aiCustomers; }3、構建一個表達式方法 public static class DbCustomersTest { /// <summary> /// 構建一個表達式方法 /// </summary> /// <param name="aiExp">表達式</param> /// <returns></returns> public static Customers GetCustomers(ExPRession<Func<IQueryable<Customers>, IQueryable<Customers>>> aiExp) { AiExpConditions<Customers> expc = new AiExpConditions<Customers>(); expc.Add(aiExp); return Customers.Data_Fetch(expc.Where(), expc.OrderBy()); } }4、調用用例測試 Customers aic = DbCustomersTest.GetCustomers(c => c.Where(o => o.CustomerID == "ALFKI")); Customers aic2 = DbCustomersTest.GetCustomers(c => c.Where(o => o.CustomerID.Contains("CO")).OrderBy(o=>o.CompanyName));