//1.创建compiled query NorthwindDataContext db = new NorthwindDataContext(); var fn = CompiledQuery.Compile( (NorthwindDataContext db2, string city) => from c in db2.Customers where c.City == city select c); //2.查询城市为London的消费者,用LonCusts集合表示,这时可以用数据控件绑定 var LonCu...
在云计算领域,LINQ(Language Integrated Query)是一种查询技术,它允许开发者使用类似于编程语言的语法来查询数据。LINQ to SQL 是一种将 LINQ 查询与 SQL 数据库进行交互的技术。 以下是一个真正复杂的 LINQ to SQL 查询示例: 代码语言:csharp 复制 var query = from order in db.Orders where order.OrderDate...
没必要这样写varlst =query.ToList();//这种思路:先查询出sql数据,再用LINQ to Object来处理“字符串聚合”varlst00 = lst.Select(d =>new{ d.ID, d.Name, d.FzCount, Fz = d.Fz.Select(o => o.Name).Aggregate((a, b) => $"{a},{b}") }).ToList();vardt =ToDataTable(lst);vardt...
若要通过使用 LINQ to SQL 获得相同的结果,您可以使用 Customer 类中已经存在的 Orders 属性引用。Orders 引用提供了执行查询和投影 CustomerID-OrderID 对所必需的信息,如下面的代码所示: VB DimdbAsNewNorthwnd("c:\northwnd.mdf")DimidQuery = _FromcustIndb.Customers, ordIncust.Orders _Wherecust.City ="...
LINQ to SQL: .NET Language-Integrated Query for Relational Data .NET Language-Integrated Query for XML Data The .NET Standard Query Operators Overview of C# 3.0 Make Your Components Really RAD with Visual Studio .NET Property Browser Microsoft .NET and Windows XP COM+ Integration with SOAP Micro...
由于SQL 中的排序存在限制,因此 LINQ to SQL 会设法将这些方法的参数的排序操作移到相应方法的结果中进行。 例如,请考虑下面这个 LINQ to SQL 查询: VB复制 DimcustQuery = _FromcustIndb.Customers _Wherecust.City ="London"_OrderBycust.CustomerID _SelectcustSkip1Take1 ...
' Query for a specific customer Dim id As String = "ALFKI" Dim targetCustomer = (From cust In db.Customers _ Where cust.CustomerID = id).First targetCustomer.CompanyName = "Dr. Frogg's Croakers" 一旦在上面的示例中分配了 CompanyName,LINQ to SQL 就会意识到更改并能够记录更改。 所有数据...
LINQ to SQL is language-agnostic. Any language built to provide Language-Integrated Query can use it to enable access to information stored in relational databases. The samples in this document are shown in both C# and Visual Basic; LINQ to SQL can be used with the LINQ-enabled version of ...
' Query for a specific customer Dim id As String = "ALFKI" Dim targetCustomer = (From cust In db.Customers _ Where cust.CustomerID = id).First targetCustomer.CompanyName = "Dr. Frogg's Croakers" 一旦在上面的示例中分配了 CompanyName,LINQ to SQL 就会意识到更改并能够记录更改。 所有数据...
以前一直觉得linq to sql生成类似where id not in (1,3,5)或where id not in (select id from ....