实体框架映射问题

Posted 2023-04-12

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【中文标题】实体框架映射问题【英文标题】：Entity Framework Mapping Question 【发布时间】：2009-06-20 14:04:24 【问题描述】：

尝试使用实体框架映射以下架构。

一个客户可以有许多关联的商店。一个商店可以有许多关联的客户每个 Store 可以有 0 个或 1 个且只有 1 个 TopCustomer（成为 TopCustomer 的条件在业务逻辑中确定）

这会在 VS 中产生以下映射。

这是数据库脚本：


USE [TestDb]
GO
/****** Object:  Table [dbo].[Customer]    Script Date: 06/20/2009 09:53:52 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Customer](
    [CustomerId] [uniqueidentifier] NOT NULL,
    [FirstName] [nvarchar](50) NOT NULL,
    [LastName] [nvarchar](50) NOT NULL,
 CONSTRAINT [PK_Customer] PRIMARY KEY CLUSTERED 
(
    [CustomerId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[Store]    Script Date: 06/20/2009 09:53:52 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Store](
    [StoreId] [uniqueidentifier] NOT NULL,
    [StoreName] [nvarchar](50) NOT NULL,
    [TopCustomer] [uniqueidentifier] NULL,
 CONSTRAINT [PK_Store] PRIMARY KEY CLUSTERED 
(
    [StoreId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[CustomerStore]    Script Date: 06/20/2009 09:53:52 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[CustomerStore](
    [CustomerId] [uniqueidentifier] NOT NULL,
    [StoreId] [uniqueidentifier] NOT NULL,
 CONSTRAINT [PK_CustomerStore] PRIMARY KEY CLUSTERED 
(
    [CustomerId] ASC,
    [StoreId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  ForeignKey [FK_CustomerStore_Customer]    Script Date: 06/20/2009 09:53:52 ******/
ALTER TABLE [dbo].[CustomerStore]  WITH CHECK ADD  CONSTRAINT [FK_CustomerStore_Customer] FOREIGN KEY([CustomerId])
REFERENCES [dbo].[Customer] ([CustomerId])
ON UPDATE CASCADE
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[CustomerStore] CHECK CONSTRAINT [FK_CustomerStore_Customer]
GO
/****** Object:  ForeignKey [FK_CustomerStore_Store]    Script Date: 06/20/2009 09:53:52 ******/
ALTER TABLE [dbo].[CustomerStore]  WITH CHECK ADD  CONSTRAINT [FK_CustomerStore_Store] FOREIGN KEY([StoreId])
REFERENCES [dbo].[Store] ([StoreId])
ON UPDATE CASCADE
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[CustomerStore] CHECK CONSTRAINT [FK_CustomerStore_Store]
GO
/****** Object:  ForeignKey [FK_Store_TopCustomer]    Script Date: 06/20/2009 09:53:52 ******/
ALTER TABLE [dbo].[Store]  WITH CHECK ADD  CONSTRAINT [FK_Store_TopCustomer] FOREIGN KEY([TopCustomer])
REFERENCES [dbo].[Customer] ([CustomerId])
GO
ALTER TABLE [dbo].[Store] CHECK CONSTRAINT [FK_Store_TopCustomer]
GO

问题：

如何在不为 Customer 类创建额外导航属性的情况下将 TopCustomer 关联映射到 Customer 的单个实例？

【问题讨论】：

抱歉，您使用哪个应用程序进行映射？ 【参考方案1】：

听起来你已经有模型工作和映射了？

但您只需要删除额外的导航属性？

如果你想删除导航属性，这很简单（虽然你不能用标准的 EF 设计器来做）。

您只需在 XML 编辑器中打开您的 EDMX 文件（在 VS 中很简单），然后从客户实体中删除不需要的 <NavigationProperty .../>。

这样关系在Model中仍然存在，但在类中你只能从 Store.TopCustomer

你不能走另一条路。

希望对你有帮助

亚历克斯