Fluent NHibernate（具有自动映射）不保存多对多连接表值

Question

我不完全是 NHibernate 专家，所以这可能是对该部门缺乏了解。我有两个具有多对多关系的简单实体

public class Category
{
    public virtual int Id { get; private set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual bool Visible { get; set; }

    public virtual IList<Product> Products { get; set; }
}

，

public class Product
{
    public virtual int Id { get; private set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual decimal Price { get; set; }
    public virtual bool Visible { get; set; }
    public virtual IList<Category> Categories { get; set; }
}

我的配置是

    public static void BuildFactory()
    {
        _factory = Fluently.Configure()
            .Database(
                MsSqlConfiguration
                    .MsSql2008
                    .ConnectionString(_connectionString)
                    .ShowSql()
            )
            .Mappings(m =>
                m.AutoMappings.Add(
                    AutoMap.AssemblyOf<Database>()
                        .Where(t => t.Namespace == "FancyStore.Models.Catalog")
                        .Override<Product>(k => 
                            k.HasManyToMany(x => x.Categories)
                                .Table("ProductsToCategories")
                                    .ParentKeyColumn("Product_id")
                                    .ChildKeyColumn("Category_id")
                                .Cascade.AllDeleteOrphan())
                        .Override<Category>(k =>
                            k.HasManyToMany(x => x.Products)
                                .Table("ProductsToCategories")
                                    .ParentKeyColumn("Category_id")
                                    .ChildKeyColumn("Product_id")
                                .Cascade.AllDeleteOrphan().Inverse())
                )
            )
            .ExposeConfiguration(SetConfiguration)
            .BuildConfiguration()
            .BuildSessionFactory();
    }

所以我开始时没有覆盖（在一些谷歌搜索建议后添加它们），并使用 ExportSchema 生成我的架构。 ExportSchema 了解多对多关系（即使没有覆盖），因为它生成了一个连接表 (ProductsToCategories)。

我想添加一些简单的测试数据，所以我这样做了，

        using (var db = new Repository<Category>())
        {
            for (int i = 0; i < 6; i++)
            {
                var cat = new Category
                {
                    Name = "Things" + i,
                    Description = "Things that are things",
                    Visible = true,
                    Products = new List<Product>()
                };

                for (int k = 0; k < 6; k++)
                {
                    var prod = new Product
                    {
                        Name = "Product" + k,
                        Description = "Product for " + cat.Name,
                        Visible = true,
                        Categories = new List<Category>(new[] { cat })
                    };
                    cat.Products.Add(prod);
                }
                db.Save(cat);
            }
        }

这可以正确保存产品和类别，但它不会保存连接表中的任何关系。查看对category.Products的调用生成的sql，它实际上是在连接表中查找产品（并且找不到任何产品，因为它是空的）

任何帮助将不胜感激:-)

编辑 ：删除了相反的问题，问题仍然发生:(

编辑2：

这是目录和产品的映射文件（注意：这个名字有点傻，但这只是一个快速原型式的交易）

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
  <class xmlns="urn:nhibernate-mapping-2.2" name="FancyStore.Models.Catalog.Product, FancyStore, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="`Product`">
    <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Id" />
      <generator class="identity" />
    </id>
    <property name="Name" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Name" />
    </property>
    <property name="Description" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Description" />
    </property>
    <property name="Price" type="System.Decimal, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Price" />
    </property>
    <property name="Visible" type="System.Boolean, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Visible" />
    </property>
    <bag cascade="all-delete-orphan" inverse="true" name="Categories" table="ProductsToCategories">
      <key>
        <column name="Product_id" />
      </key>
      <many-to-many class="FancyStore.Models.Catalog.Category, FancyStore, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">
        <column name="Category_id" />
      </many-to-many>
    </bag>
  </class>
</hibernate-mapping>

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
  <class xmlns="urn:nhibernate-mapping-2.2" name="FancyStore.Models.Catalog.Category, FancyStore, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="`Category`">
    <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Id" />
      <generator class="identity" />
    </id>
    <property name="Name" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Name" />
    </property>
    <property name="Description" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Description" />
    </property>
    <property name="Visible" type="System.Boolean, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Visible" />
    </property>
    <bag cascade="all-delete-orphan" name="Products" table="ProductsToCategories">
      <key>
        <column name="Category_id" />
      </key>
      <many-to-many class="FancyStore.Models.Catalog.Product, FancyStore, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">
        <column name="Product_id" />
      </many-to-many>
    </bag>
  </class>
</hibernate-mapping>

Answer 1

我可能是错的，但看起来你将双方的关系标记为“反向”。

您应该仅对关系的一侧执行此操作，并确保在另一侧调用Save。

另外，我认为在保存之前，双方的关系都必须有效（除了您已经执行的操作之外，还将 cat 添加到 prod.Categories 中）。

诚然，我对这些关系的理解是模糊的，但这是我几个月来的研究得出的结论（并解决了我自己的一些问题）。

Answer 2

@马特·布里格斯，我已经弄清楚了。您必须将一个关系设置为 Inverse() 并保存另一个实体，添加对两个实体的引用 (prod.Categories.Add() + cat.Products.Add()) 并提交事务。除非您提交，否则不会生成连接表的查询。 – HeavyWave 5 月 13 日 12:43

Answer 3

你在关联的错误一侧有逆。逆的意思是“对方管理这个关联”。

您需要的是删除类别上的 Inverse 并将其放在产品上，或者将产品更改为“拥有”实体，如下所示：

//make sure to add it to BOTH sides of the association
product.Categories.Add(cat);
cat.Products.Add(product);

db.Save(cat);  //if Product has Inverse
/* or */
db.Save(prod); //if Category has Inverse

Answer 4

如果您要在自动映射之前先对产品和类别应用流畅映射，该怎么办？例如，

public class Product
{
    public virtual int Id { get; private set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual decimal Price { get; set; }
    public virtual bool Visible { get; set; }
    public virtual IList<Category> Categories { get; set; }

    public Product()
    {
        Categories = new List<Category>();
    }
}

public class ProductMap : ClassMap<Product>
{
    Id(x => x.Id);
    Map(x => x.Name);
    Map(x => x.Description);
    Map(x => x.Price);
    Map(x => x.Visible);
    HasManyToMany(x => x.Categories)
      .Table("ProductsToCategories")
      .ParentKeyColumn("Product_id")
      .ChildKeyColumn("Category_id")
      .Cascade.AllDeleteOrphan();
}

public class Category
{
    public virtual int Id { get; private set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual bool Visible { get; set; }
    public virtual IList<Product> Products { get; set; }

    public Category()
    {
        Products = new List<Product>();
    }
}

public class CategoryMap : ClassMap<Category>
{
    Id(x => x.Id);
    Map(x => x.Name);
    Map(x => x.Description);
    Map(x => x.Visible);
    HasManyToMany(x => x.Products)
      .Table("ProductsToCategories")
      .ParentKeyColumn("Category_id")
      .ChildKeyColumn("Product_id")
      .Cascade.AllDeleteOrphan().Inverse();
}

通过配置，

public static void BuildFactory()
{
    _factory = Fluently.Configure()
        .Database(
            MsSqlConfiguration
                .MsSql2008
                .ConnectionString(_connectionString)
                .ShowSql()
        )
        .Mappings(m => {
            m.FluentMappings.AddFromAssemblyOf<Database>();
            m.AutoMappings.Add(
              AutoMap.AssemblyOf<Database>()
              .Where(t => t.Namespace == "FancyStore.Models.Catalog"));
        })
        .ExposeConfiguration(SetConfiguration)
        .BuildConfiguration()
        .BuildSessionFactory();
}