EF 三表Join，三表Left Join ：http://m.tnblog.net/xiuxin/article/details/2743
Entity Framework使用汇总 EF的发展历程还是先来说一下EF从诞生到现在这几年的发展历程吧。在EF最初的版本中,作为一个ORM组件其通过EDM文件(里面是一些xml)来配置数据库与实体类之间的映射,实现数据进出数据库的控制。最初的版本中只支持Database First,即由已有数据库结构生成EDM,继而得到实体类。后来EF在4.0版本...
如你所料,因为现在存在3个表,所以使用了2次JOIN。一点补充之前的示例中用到多次HasForeignKey()方法来指定外键,如果实体类中不存在表示外键的属性,我们可以用下面的方式指定外键列,这样这个外键列只存在于数据库,不存在于实体中:1 HasOptional(p => p.Invoice).WithMany().Map(m => m.MapKey("DbOnly...
场景:在实际的项目中使用EntityFramework都会遇到使用Ef处理连接查询的问题,这里做一些小例子如何通过Linq语法处理内连接(inner join)、外连接(left/right outer join); 废话不多说先看实体类: 1.内连接: Linq: var query = from st in context.SchoolBoys join gl in context.SchoolGirls on st.GirlfriendId e...
场景:在实际的项目中使用EntityFramework都会遇到使用Ef处理连接查询的问题,这里做一些小例子如何通过Linq语法处理内连接(inner join)、外连接(left/right outer join); 废话不多说先看实体类: 1.内连接: Linq: varquery =fromstincontext.SchoolBoysjoinglincontext.SchoolGirlsonst.GirlfriendIdequalsgl.Idselectnew{...
join u in context.User on u.UserId equals cuc.UserId into ucuc from y in ucuc.DefaultIfEmpty() select new { x.ColorId, x.ColorName, x.ColorId == 0 ? false : true }; Please refer to the following link for more samples of how to do multiple LEFT joins in LINQ:http://stack...
Right-click on your project in Solution Explorer and select Properties. Select Microsoft Entity Framework June 2011 CTP from the Target framework drop-down (see Figure 1). Press Ctrl+S to save the project. Visual Studio asks for permission to close and reopen the project; click Yes. Add a ...
Microsoft.EntityFrameworkCore.Migrations Microsoft.EntityFrameworkCore.Migrations.Design Microsoft.EntityFrameworkCore.Migrations.Operations Microsoft.EntityFrameworkCore.Migrations.Operations.Builders Microsoft.EntityFrameworkCore.Query Microsoft.EntityFrameworkCore.Query.SqlExpressions ...
建立ManyToManyJoinEntityTypeConvention 的新執行個體。 C# 複製 public ManyToManyJoinEntityTypeConvention (Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure.ProviderConventionSetBuilderDependencies dependencies); 參數 dependencies ProviderConventionSetBuilderDependencies 參數物件,包含...
Supports specifying property and value to be set in ExecuteUpdate method with chaining multiple calls for updating multiple columns. This type does not have any constructor or implementation since it is used inside LINQ query solely for the purpose of creating expression tree. ShapedQueryCompilingEx...