Question

我有一个名为ActivityLog的实体：

    public class ActivityLog : EntityModel<ActivityLog>
{
    public virtual int activityID { get; set; }
    public virtual int entityType { get; set; }
    public virtual int entityID { get; set; }
    public virtual string entityName { get; set; }
    public virtual int action { get; set; }
    public virtual int parentType { get; set; }
    public virtual int parentID { get; set; }
    public virtual string parentName { get; set; } }
    public virtual string userName { get; set; }
    public virtual int instanceID { get; set; }
    public virtual DateTime? timeStamp { get; set; }
    public virtual DateTime? groupTimeStamp { get; set; }
}

和一个名为Activity的DTO类：

    public class Activity
{
    public virtual int activityID { get; set; }
    public virtual int entityType { get; set; }
    public virtual int entityID { get; set; }
    public virtual string entityName { get; set; }
    public virtual int action { get; set; }
    public virtual int parentType { get; set; }
    public virtual int parentID { get; set; }
    public virtual string parentName { get; set; }
    public virtual string userName { get; set; }
    public virtual int instanceID { get; set; }
    public virtual DateTime? timeStamp { get; set; }
    public virtual DateTime? groupTimeStamp { get; set; }
    public IList<Activity> activities { get; set; }
}

我需要通过转换来填充实体中的DTO，我还要将IList<Activity>填入包含parentType和parentID的实体。用最少的查询来做最好的方法是什么？

Answer 1

IList<ActivityLog> activityLogs = ...;

var activities = session.Query<Activity>()
    .WhereRestrictionOn(a => a.Parent.Id).IsIn(activityLogs.Select(al => al.parentID))
    .WhereRestrictionOn(a => a.Parent.Type).IsIn(activityLogs.Select(al => al.parentType))
    .AsEnumerable()
    .ToLookUp(a => new { ParentId = a.Parent.Id, ParentType = a.Parent.Type });

var results = activityLogs
    .Select(al => new ActivityDTO
    {
        activityID = al.activityID,
        entityType = al.entityType,
        ...
        activities = activities[new { ParentId = al.parentID, ParentType = al.parentType }].ToList()
    });

Answer 2

您可以使用ProjectionList和AliasToBean resulttransformer：

var criteria = session.CreateCriteria <ActivityLog>();
criteria.SetProjection (Projections.ProjectionList()
                                     .Add (Projections.Property ("activityID"), "activityID")
                                     ...);

criteria.SetResultTransformer (Transformers.AliasToBean <Activity>());

return criteria.List<Activity>();

使用转换使用DTO的属性列表填充DTO

2 个答案: