c# - NHibernate查询问题

Question

这些是我的实体(简化):

public class IdentificationRequest
{
    private int id;
        private ICollection<IdentificationRequestStateHistoryItem> stateHistoryItems;

        public virtual string Id
        {
            get { return id; }
            private set { id = value; }
        }                

        public virtual IEnumerable<IdentificationRequestStateHistoryItem> StateHistoryItems
        {
            get { return stateHistoryItems; }
            private set { stateHistoryItems = new List<IdentificationRequestStateHistoryItem>(value); }
        }

        public void ChangeState(IdentificationRequestState state)
        {
        // state transition here
            var stateHistoryItem = new IdentificationRequestStateHistoryItem(state, this);
            stateHistoryItems.Add(stateHistoryItem);
        }     
}


public class IdentificationRequestStateHistoryItem
{
    private int id;
        private IdentificationRequestState state;
        private EntityTimestamp timestamp;

        public virtual string Id
        {
            get { return id; }
            private set { id = value; }
        }                

    public virtual IdentificationRequestState State
    {
        get { return state; }
        private set { state = value; }
    }

    public virtual EntityTimestamp Timestamp
    {
        get { return timestamp; }
        private set { timestamp = value; }
        }
}



public class IdentificationRequestState
{
    // possible states are
    // Received, then id = 10
    // Finished, then id = 20   
    private int id; 

    private string name;

        public virtual string Name
        {
            get { return name; }
            private set { name = value; }
        }

        public virtual string Id
        {
            get { return id; }
            private set { id = value; }
        }        
}

public class EntityTimestamp
    {
        private DateTime createdOn;


        public virtual DateTime CreatedOn
        {
            get { return createdOn; }
            private set { createdOn = value; }
        }

        private IUser createdBy;


        public virtual IUser CreatedBy
        {
            get { return createdBy; }
            private set { createdBy = value; }
        }

        private DateTime changedOn;


        public virtual DateTime ChangedOn
        {
            get { return changedOn; }
            private set { changedOn = value; }
        }

        private IUser changedBy;


        public virtual IUser ChangedBy
        {
            get { return changedBy; }
            private set { changedBy = value; }
        }
}        

所以上面的内容如下，并且在数据库中的设计也是如此。

IdentificationRequest 可以跟踪其 IdentificationRequestState 转换。因此，每次分配新的 IdentificationRequestState 时，都会创建一个新的 IdentificationRequestStateHistoryItem 并将其放入多个历史记录项的集合中。这意味着，当前的 IdentificationRequestState 是最后添加的(由createdOn 日期表示)。

现在我的问题是，一个查询会是什么样子，它列出了所有 IdentificationRequest 的当前状态为“已接收”或“已完成”。

这是我到目前为止得到的:

private ICollection<IdentificationRequest> GetByCurrentState(IdentificationRequestState state)
{
    var session = GetCurrentSession();

    var subCriteria = DetachedCriteria.For(typeof(IdentificationRequestStateHistoryItem))            
        .SetProjection(Projections.Property("identificationRequest.Id" ));

    subCriteria.Add(Restrictions.Eq("State", state));

    var criteria = session
        .CreateCriteria(typeof (IdentificationRequest))
        .Add(Subqueries.PropertyIn("Id", subCriteria))
        .SetResultTransformer(new NHibernate.Transform.DistinctRootEntityResultTransformer());

   return criteria.List<IdentificationRequest>();          
}

但是，当使用此查询并搜索当前状态为“已接收”的标识请求时，我也会收到当前状态为“已完成”的请求，因为该请求之前的状态为“已接收”。所以我需要用 Max(CreatedOn) 做一些事情或者等等......？

NHibernate 映射:

   <class name="IdentificationRequest" table="IdentificationRequest">

    <id name="Id" column="IdentificationRequestId" unsaved-value="-1">
      <generator class="identity"/>
    </id>

    <bag name="stateHistoryItems" access="field" order-by="CreatedOn desc" fetch="join" cascade="all-delete-orphan" lazy="false">
      <key column="IdentificationRequestId"/>
      <one-to-many class="IdentificationRequestStateHistoryItem"/>
    </bag>

  </class>


    <class name="IdentificationRequestStateHistoryItem" table="IdentificationRequestStateHistoryItem">

      <id name="Id" column="IdentificationRequestStateHistoryItemId" unsaved-value="-1">
        <generator class="identity"/>
      </id>

      <many-to-one name="identificationRequest" access="field" lazy="false" cascade="none" column="IdentificationRequestId" class="IdentificationRequest"></many-to-one>

      <many-to-one name="State" lazy="false" fetch="join" cascade="none" column="IdentificationRequestStateId" class="IdentificationRequestState"></many-to-one>

      <component name="Timestamp" class="EntityTimestamp">
        <property name="CreatedOn"/>
        <component name="CreatedBy" class="User">
          <property name="Name" column="CreatedBy" />
        </component>
        <property name="ChangedOn"/>
        <component name="ChangedBy" class="User">
          <property name="Name" column="ChangedBy" />
        </component>
      </component>

    </class>


  <class name="IdentificationRequestState" table="IdentificationRequestState">

    <id name="Id" column="IdentificationRequestStateId" unsaved-value="-1">
      <generator class="assigned"/>
    </id>

    <property name="Name"/>

  </class>    

Answer 1

通过具有IdentificationRequest.CurrentState 属性，您可以省去很多麻烦。

您对 max() 的想法是正确的。您可以添加另一个子标准，在其中获取该请求的所有请求状态的最大值(日期)，然后向现有子标准添加限制，使其日期 = 该最大日期。恶心，但这是我能想到的唯一方法。