隆重推荐：DAC 4.0 全新发布-白红宇

隆重推荐：DAC 4.0 全新发布

阅读量：7059 次

发布时间：2019-06-28

本文共 3645 字，大约阅读时间需要 12 分钟。

是一个全新的版本，几乎全部重写了以前的代码，设计的结构也简化很多，基于.net4,使用lambda表达式代替反射，去除大量过时的功能（如DataTable和DataSet的相关功能等），去除自定义表达式部分，通过解析lambda表达式实现自定义条件查询。使用.net自带Configuration功能，只要web.config或app.config，不需要额外的配置文件，方便配置使用；去除xml mapping方式，支持DLinq属性。支持多种数据库（已测试sql server, mysql, sqlite及oracle), 支持(ubuntu 11.10 + mono 2.10.5 + mysql 5.1.58测试通过)。

代码示例：

初启化,通过配置文件或connection string构造DataContext:

var dc = new DataContext("RaisingStudio.Data.TestProject.Properties.Settings.DefaultConnectionString"); 或 var dc = new DataContext("server=localhost;User Id=root;password=root;database=test;");

lambda表达式查询：

var q = this.dc.Query
     
      (i => i.Name == "test" && i.Status == "ok");

或linq查询：

var q = from s in dc.GetQuery
     
      () where s.SuppId > 0 && s.Name == "for Test3" select s;

增删改：

this.dc.Insert
     
      (new Product {
       ProductId = Guid.NewGuid().ToString(),         CategoryId = categoryId,         Name = "for Test4"                }); this.dc.Delete
      
       (suppId); this.dc.Update
       
        (product); this.dc.Save
        
         (category);

通过主键获取单个实例：

var product = this.dc.GetEntity
     
      (productId);

支持排序和分页：

List
     
       items = this.dc.Query
      
       (ExpressionExtension.Empty
       
        ().Take(3)).ToList(); var q = (from i in this.dc.GetQuery
        
         () select i).Skip(1).Take(2); int count = this.dc.Query
         
          (ExpressionExtension.Empty
          
           ().Skip(1)).Count();

部分列：

this.dc.Save
     
      (item, new string[] { "UnitCost" }); this.dc.Insert
      
       (item, new Expression
       
        
         >[] {         i => i.ItemId,         i => i.Name,         i => i.ListPrice,         i => i.ProductId,         i => i.Status });

无实例类查询：

Command command = new Command("SELECT * FROM Product WHERE CategoryId = @p1"); command.AddParameter("@p1", categoryId); var q = this.dc.Query(command); int count = 0; foreach (dynamic p in q) {
        Assert.IsNotNull(p);      Assert.AreEqual(p.CategoryId, categoryId);      count++; }

事务处理：

this.dc.BeginTransaction(); try             {
   int result = this.dc.Insert
     
      (new Supplier                 {
                       Name = "s for Test6",                     Status = "done",                     City = "dalian"                 }); int suppId = Convert.ToInt32(this.dc.GetIdentity
      
       ());                 result = this.dc.Delete
       
        (suppId);                 Category category = new Category                 {
                       CategoryId = Guid.NewGuid().ToString(),                     Name = "c for Test6",                     Descn = "d for Test6"                 };                                Product product = new Product                 {
                       ProductId = Guid.NewGuid().ToString(),                     Name = "p for Test6",                     Descn = "d for Test6",                     CategoryId = category.CategoryId                 };                 result = this.dc.Insert
        
         (category);                 result = this.dc.Insert
         
          (product); this.dc.CommitTransaction();             } catch (Exception ex)             {
   this.dc.RollbackTransaction(); throw ex;             }

配置文件示例：

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