Question

我在使用Entity Framework从我的DbContext对象生成的SQL中遇到了很多重复的连接。这是我的基本结构

CatalogTable（ CatalogID int主键）

CategoryTable（ CategoryID int PRIMARY KEY， CatalogID int NOT NULL ）

DepartmentTable（ DepartmentID int PRIMARY KEY， CatalogID int NOT NULL）

产品（ CatalogID int NOT NULL， CategoryID int NOT NULL， DepartmentID int NOT NULL ）

很简单，产品必须有目录，类别和部门。我已经设置了所有导航属性来反映这一点。是的，“产品”可以通过类别或部门间接与目录相关联。但由于有两种可能的路径，我选择明确指出产品属于目录。

因此问题变成了EF继续加入这些必需的关系，基本上为类别和部门吐出了双连接。

型号：

           //catalogs
            modelBuilder.Entity<Catalog>().ToTable("Catalog.Catalogs");
            modelBuilder.Entity<Catalog>().HasKey(k => k.CatalogID);

            //products
            modelBuilder.Entity<CatalogItem>().ToTable("Catalog.Products");
            modelBuilder.Entity<CatalogItem>().HasKey(k => k.ProductID);
            modelBuilder.Entity<CatalogItem>().HasRequired(req => req.CatalogCategory).WithMany().Map(m => m.MapKey("CatalogCategoryID"));
            modelBuilder.Entity<CatalogItem>().HasRequired(req => req.CatalogDepartment).WithMany().Map(m => m.MapKey("CatalogDepartmentID"));
            modelBuilder.Entity<CatalogItem>().HasRequired(req => req.Catalog).WithMany().Map(m => m.MapKey("CatalogID"));

            //departments
            modelBuilder.Entity<CatalogDepartment>().ToTable("Catalog.Departments");
            modelBuilder.Entity<CatalogDepartment>().HasKey(k => k.CatalogDepartmentID);
            modelBuilder.Entity<CatalogDepartment>().HasRequired(req => req.Catalog).WithMany().Map(m => m.MapKey("CatalogID"));

            //categories
            modelBuilder.Entity<CatalogCategory>().ToTable("Catalog.Categories");
            modelBuilder.Entity<CatalogCategory>().HasKey(k => k.CatalogCategoryID);
            modelBuilder.Entity<CatalogCategory>().HasRequired(req => req.Catalog).WithMany().Map(m => m.MapKey("CatalogID"));

的LINQ：

var query = Products
    .Include(inc=>inc.CatalogCategory)
    .Include(inc=>inc.CatalogDepartment)
    .Include(inc=>inc.Catalog);



query.ToList();

生成的Sql：

SELECT *
FROM     [Catalog].[Products] AS [Extent1]
INNER JOIN [Catalog].[Categories] AS [Extent2] ON [Extent1].[CatalogCategoryID] = [Extent2].[CatalogCategoryID]
LEFT OUTER JOIN [Catalog].[Categories] AS [Extent3] ON [Extent1].[CatalogCategoryID] = [Extent3].[CatalogCategoryID]
LEFT OUTER JOIN [Catalog].[Departments] AS [Extent4] ON [Extent1].[CatalogDepartmentID] = [Extent4].[CatalogDepartmentID]
LEFT OUTER JOIN [Catalog].[Catalogs] AS [Extent5] ON [Extent1].[CatalogID] = [Extent5].[CatalogID]

您可以清楚地看到“类别”被连接两次;一次作为内部联接，一次作为外部联接。

这里的任何想法如何干净（和准确）地建立关系但防止重复绑定？谢谢！

EntityFramework dbContext导航属性导致重复的连接

0 个答案: