问NHibernate:如何测试多对一关系是懒惰的？
EN

Stack Overflow用户

提问于 2010-05-20 19:40:56

回答 1查看 396关注 0票数 1

我有一个简单的多对一关系(订单有一个下订单的客户)。下面是我的订单映射中的except：

<many-to-one name="Customer" column="FK_CUSTOMERS" class="MyApp.Customer, MyApp" 
not-null="true" lazy="proxy" cascade="none" />

然而，以下内容并未通过：

configuration.GetClassMapping(typeof(Order))
  .ReferenceablePropertyIterator.FirstOrDefault(p=>p.Name=="Customer")
  .IsLazy
  .ShouldBeTrue();

怎么回事？

nhibernate

nhibernate-mapping

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回答 1

Stack Overflow用户

发布于 2010-05-20 20:55:12

我正在查看源代码，似乎NH对IsLazy的看法有点怪异。这是2010-01-26的最后一次更改

get
            {
-               if (propertyValue is ToOne)
-               {
-                   // both many-to-one and one-to-one are represented as a
-                   // Property.  EntityPersister is relying on this value to
-                   // determine "lazy fetch groups" in terms of field-level
-                   // interception.  So we need to make sure that we return
-                   // true here for the case of many-to-one and one-to-one
-                   // with lazy="no-proxy"
-                   //
-                   // * impl note - lazy="no-proxy" currently forces both
-                   // lazy and unwrap to be set to true.  The other case we
-                   // are extremely interested in here is that of lazy="proxy"
-                   // where lazy is set to true, but unwrap is set to false.
-                   // thus we use both here under the assumption that this
-                   // return is really only ever used during persister
-                   // construction to determine the lazy property/field fetch
-                   // groupings.  If that assertion changes then this check
-                   // needs to change as well.  Partially, this is an issue with
-                   // the overloading of the term "lazy" here...
-                   ToOne toOneValue = (ToOne)propertyValue;
-                   return toOneValue.IsLazy && toOneValue.UnwrapProxy;
-               }
+               // NH Specific: Hibernate doesn't make a distinction between
+               // lazy and no-proxy, but NHibernate does. While Hibernate tracks
+               // just whatever a property is lazy, we need to track lazy/no-proxy seperatedly.
+               
                return isLazy;
            }

因此，这取决于您使用的版本，但如果您将此属性映射为noproxy (即.UnwrapProxy)。这给你带来了什么？

var to1 = configuration.GetClassMapping(typeof(Order))
  .ReferenceablePropertyIterator.FirstOrDefault(p=>p.Name=="Customer")
  .Value as NHibernate.Mapping.ToOne;

to1.IsLazy.ShouldBeTrue();
to1.UnwrapProxy.ShouldBeFalse();