c# - NHibernate查询问题

这些是我的实体（简体）：

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; }
        }
}

因此，上面的内容与下面的内容类似，并且在数据库中也是如此。

IdentificationRequest可以跟踪其IdentificationRequestState过渡。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项的集合中。这意味着，当前IdentificationRequestState是最后添加的IdentificationRequest（以createdOn日期表示）。

所以现在我的问题是，查询看起来如何，其中列出了所有谁的当前状态为已接收或已完成。

这是我到目前为止所得到的：

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其当前状态为Received的标识请求时，由于该请求的状态为以前的Received，因此我也会获取其当前状态为Finished的请求。所以我需要用Max（CreatedOn）做些什么？

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>

最佳答案

通过拥有IdentificationRequest.CurrentState属性，您将省去很多麻烦。

您对max（）的想法是正确的。您可以添加另一个子条件，在其中获取该请求的所有请求状态的max（date），然后对现有子条件添加限制，以使其日期=该最大日期。毛，但这是我唯一能想到的方法。