NHibernate用子查询计数另一个实体

本文关键字：另一个实体查询 NHibernate | 更新日期: 2023-09-27 18:10:55

我有两个实体:

User
{
    UserGuid,
    Address,
    .
    .
    .
    EmailCount // This is not a column in the database, 
               // I just wanna get the count number from the UserEmail table
               // and map the value to this property
}
UserEmail
{
    UserGuid,
    Timestamp
}

问题是我如何在NHibernate中使用子查询获得电子邮件计数?

到目前为止，我有这个，但它不工作。任何想法?

User userEntity = null;
var subQuery = QueryOver.Of<UserEmail>()
    .Where(ue => ue.UserGuid == userEntity.UserGuid)
    .ToRowCountQuery();                       
return _session.StatefulSession.QueryOver(() => userEntity)
          .WithSubquery.WhereValue("EmailCount").Eq(subQuery)
          .List();

NHibernate用子查询计数另一个实体

这将是如何使用subquery获得内联计数与QueryOver语法的方式:

User userEntity = null;
var subQuery = QueryOver
    .Of<UserEmail>()
    .Where(ue => ue.UserGuid == userEntity.UserGuid)
    .ToRowCountQuery(); 
var list = _session.StatefulSession
    .QueryOver<User>(() => userEntity)
    .SelectList(projections => projections
        .Select(x => x.UserGuid)
             .WithAlias(() => userEntity.UserGuid)
        .Select(x => x.Address)
             .WithAlias(() => userEntity.Address)
        // any property to be selected
        ... 
        // INLINE COUNT
        // our subquery placed into play
        .SelectSubQuery(subQuery)
             // this will populate virtual/not mapped EmailCount
             .WithAlias(() => userEntity.EmailCount) 
    )
    .TransformUsing(Transformers.AliasToBean<User>())
    //.Take(10).Skip(100) // paging
    .List();