nHibernate 延迟加载/代理对象 - 持久性问题

Question

[使用映射文件更新]

今天遇到了延迟加载/代理对象持续存在的问题。

它涉及两个类：发票和地址。发票有一个地址属性。这两个类都设置为延迟加载，并且所有方法都是虚拟的。

在代码中，我执行了 Invoice.address = HomeCompany.address，并且可以在运行时验证 Invoice.address 是否设置正确（Invoice.address 属性已正确分配“地址代理”）。然而，当发票对象被持久化时，发票表中的“addresss_id”列将被设置为“0”。但是，如果我通过添加“Lazy = False”来更改地址的映射文件，一切都会正常工作（invoice.address 属性设置为完整的实例化地址）。

使用 nHibernate 2.1.2 这让我发疯。

[注意：nhibernate 不会产生任何错误]

<?xml version="1.0" encoding="utf-8" ?> 
<hibernate-mapping default-access="field.camelcase-underscore" xmlns="urn:nhibernate-mapping-2.2">
<class name="TMS.Business.invoice, TMS.Business"  dynamic-update="true" optimistic-lock="all" table="invoice">

    <id name="document_id" type="Int32">
        <generator class="assigned" />
    </id>

    <property name="create_date" />
    <many-to-one name="last_updt_user" column="last_updt_userid"/>
    <property name="last_updt_datetime" />

    <property name="amount" />
    <property name="approved_flag"/>
    <property name="ba_document_date" />
    <property name="ba_document_no" not-null="true"/>
    <property name="comment" not-null="true"/>
    <property name="document_no" />
    <property name="document_no_construct"/>
    <property name="dry_gas_billing_date" />
    <property name="due_date" />
    <property name="fin_batch_no" />
    <property name="fin_interface_type_cd"/>
    <property name="fin_process_datetime" />        
    <property name="invoice_date" />
    <property name="netout_flag"/>
    <property name="override_amount" />
    <property name="receipt_date" />
    <property name="void_flag"/>

    <many-to-one name="accountant_user" column="accountant_userid"/> 
    <many-to-one name="ba" column="ba_id" property-ref="_ba_id" /> 
    <many-to-one name="ba_addr" column="ba_addr_id" property-ref="_ba_address_id" /> 
    <many-to-one name="ba_contact" column="ba_contact_id" property-ref="_ba_contact_id" /> 
    <many-to-one name="dry_gas_billing_type" column="dry_gas_billing_type_cd" property-ref="_code_key" />
    <many-to-one name="internal_ba" column="internal_ba_id" property-ref="_ba_id" />
    <many-to-one name="invoice_subtype" column="invoice_subtype_cd" property-ref="_code_key" />
    <many-to-one name="invoice_type" column="invoice_type_cd" property-ref="_code_key" />
    <many-to-one name="payment_method" column="payment_method_cd" property-ref="_code_key" />
    <many-to-one name="payment_term" column="payment_term_id" />
    <many-to-one name="remit_to_addr" column="remit_to_addr_id" property-ref="_ba_address_id"/>

    <bag name="document_histories" lazy="true" cascade="none" inverse="true" where ="linked_table = 'invoice'" order-by="document_history_id DESC">
        <key column="linked_pk"/>
        <one-to-many class="TMS.Business.document_history, TMS.Business"/>
    </bag>
    <bag name="trxn_pricelines" lazy="true" cascade="none" inverse="true">
        <key column="document_id"/> 
        <one-to-many class="TMS.Business.trxn_priceline, TMS.Business"/>
    </bag>      

</class>

---

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping default-access="field.camelcase-underscore" xmlns="urn:nhibernate-mapping-2.2">
<class name="TMS.Business.ba_address, TMS.Business" optimistic-lock="version" table="_ba_address">

    <id name="item_guid" type="Guid">
        <generator class="guid" />
    </id>
    <version name="version" />

    <property name="active_flag" />
    <property name="address" />
    <property name="city" />
    <property name="county" />
    <property name="remarks" />
    <property name="zip" />

    <many-to-one name="business_associate" column="business_associate_guid" />
    <many-to-one name="country" column="country_code" />
    <many-to-one name="state" column="state_code" />

    <property name="_ba_address_id" generated="insert" update="false" insert="false"/>  

</class>

Answer 1

如果您使用地址的主键 (id) 映射 Invoice.Address，则不会发生这种情况。

<class name="TMS.Business.invoice, TMS.Business"  dynamic-update="true" optimistic-lock="all" table="invoice">

    <id name="document_id" type="Int32">
        <generator class="assigned" />
    </id>
    <many-to-one name="ba_addr" column="ba_addr_id"  /> 
</class>

<class name="TMS.Business.ba_address, TMS.Business" optimistic-lock="version" table="_ba_address">
    <id name="item_guid" type="Guid">
        <generator class="guid" />
    </id>
</class>

所描述的行为听起来像是 _ba_address_id 被映射为字段，但您的映射文件表明它是一个属性。然而，前导下划线和小写名称表明您正在映射字段而不是属性。

如果这实际上是一个字段，那么这就是您的问题的原因。为了加载代理对象，您需要访问它的（虚拟）属性或方法之一。