Question

我有一个6级层次结构的数据库和一个域模型。像这样的东西：

类别 -SubCategory -容器 -DataDescription |元数据 -data

我正在使用的映射遵循以下模式：

  <class name="Category, Sample" table="Categories">
    <id name="Id" column="Id" type="System.Int32" unsaved-value="0">
      <generator class="native"/>
    </id>    
    <property name="Name" access="property" type="String" column="Name"/>
    <property name="Metadata" access="property" type="String" column="Metadata"/>
    <bag name="SubCategories" 
         cascade="save-update" 
         lazy="true" 
         inverse="true">
      <key column="Id" foreign-key="category_subCategory_fk"/>
      <one-to-many class="SubCategory, Sample" />
    </bag>
  </class>

<class name="SubCategory, Sample" table="SubCategories">
    <id name="Id" column="Id" type="System.Int32" unsaved-value="0">
        <generator class="native"/>
    </id>
    <many-to-one name="Category"
                 class="Category, Sample"
                 foreign-key="subCat_category_fk"/>

    <property name="Name" access="property" type="String"/>
    <property name="Metadata" access="property" type="String"/>

    <bag name="Containers"
         inverse="true"
         cascade="save-update"
         lazy="true">
        <key column="Id" foreign-key="subCat_container_fk" />
        <one-to-many class="Container, Sample" />
    </bag>
</class>

<class name="Container, Sample" table="Containers">
    <id name="Id" column="Id" type="System.Int32" unsaved-value="0">
        <generator class="assigned"/>
    </id>
    <many-to-one name="SubCategory"
                 class="SubCategory,Sample"                  
                 foreign-key="container_subCat_fk"/>    

    <property name="Name" access="property" type="String" column="Name"/>

    <bag name="DataDescription" cascade="all" lazy="true" inverse="true">
        <key column="Id" foreign-key="container_ DataDescription_fk"/>
        <one-to-many class="DataDescription, Sample" />
    </bag>

    <bag name="MetaData" cascade="all" lazy="true" inverse="true">
        <key column="Id" foreign-key="container_metadata_cat_fk"/>
        <one-to-many class="MetaData, Sample" />
    </bag>
</class>

出于某种原因，当我尝试保存类别（附带子类别，容器等）时，我从数据库中获得了外键违规。

代码是这样的（Pseudo）。

var category = new Category();
var subCategory = new SubCategory();
var container = new Container();
var dataDescription = new DataDescription();
var metaData = new MetaData();

category.AddSubCategory(subCategory);
subCategory.AddContainer(container);
container.AddDataDescription(dataDescription);
container.AddMetaData(metaData);

Session.Save(category);

以下是此测试的日志：

DEBUG NHibernate.SQL - INSERT INTO Categories (Name, Metadata) VALUES (@p0, @p1); select SCOPE_IDENTITY(); @p0 = 'Unit test', @p1 = 'unit test'

DEBUG NHibernate.SQL - INSERT INTO SubCategories (Category, Name, Metadata) VALUES (@p0, @p1, @p2); select SCOPE_IDENTITY(); @p0 = '1', @p1 = 'Unit test', @p2 = 'unit test'

DEBUG NHibernate.SQL - INSERT INTO Containers (SubCategory, Name, Frequency, Scale, Measurement, Currency, Metadata, Id) VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7); @p0 = '1', @p1 = 'Unit test', @p2 = '15', @p3 = '1', @p4 = '1', @p5 = '1', @p6 = 'unit test', @p7 = '0'

ERROR NHibernate.Util.ADOExceptionReporter - The INSERT statement conflicted with the FOREIGN KEY constraint "subCat_container_fk". The conflict occurred in database "Sample", table "dbo.SubCategories", column 'Id'.

向对象添加项目的方法总是如下：

public void AddSubCategory(ISubCategory subCategory)
{
    subCategory.Category = this;
    SubCategories.Add(subCategory);
}

我错过了什么？

谢谢， nisbus

Answer 1

我发现了错误。

我需要在映射中为一对多和多对一的名称命名列，以使其正常工作。

正确的映射看起来像这样：

 <class name="Category, Sample" table="Categories">
    <id name="Id" column="Id" type="System.Int32" unsaved-value="0">
      <generator class="native"/>
    </id>    
    <property name="Name" access="property" type="String" column="Name"/>
    <property name="Metadata" access="property" type="String" column="Metadata"/>
    <bag name="SubCategories" 
         cascade="save-update" 
         lazy="true" 
         inverse="true">
      <key column="Category_Id" foreign-key="category_subCategory_fk"/>
      <one-to-many class="SubCategory, Sample" />
    </bag>
  </class>

<class name="SubCategory, Sample" table="SubCategories">
        <id name="Id" column="Id" type="System.Int32" unsaved-value="0">
                <generator class="native"/>
        </id>
        <many-to-one name="Category"
                                 class="Category, Sample"
                                 column="Category_Id"
                                 foreign-key="subCat_category_fk"/>

        <property name="Name" access="property" type="String"/>
        <property name="Metadata" access="property" type="String"/>

        <bag name="Containers"
                 inverse="true"
                 cascade="save-update"
                 lazy="true">
                <key column="Container_Id" foreign-key="subCat_container_fk" />
                <one-to-many class="Container, Sample" />
        </bag>
</class>

现在一切都很好。

谢谢， nisbus

Nhibernate多级层次结构保存错误？

1 个答案: