Question

我希望NHibernate生成以下SQL，但我正在使用下面的代码

   SELECT rt.Id 
   FROM ClientContact cc  
     JOIN ClientContact_DefaultRequest d on d.ClientContactID = cc.Id
     JOIN RequestType rt on d.RequestTypeId = rt.Id
   WHERE 
     cc.Id = ContactId



public class GetDefaultRequestsForContact : SimpleQuery<IEnumerable<RequestType>>, IGetDefaultRequestsForContact
{
    public int ContactId { private get; set; }

    public GetDefaultRequestsForContact(ISession session) : base(session) { }

    public override IEnumerable<RequestType> Execute()
    {
        var x = Session.QueryOver<ClientContact>()
            .Where(c => c.Id == ContactId)
            .JoinQueryOver<RequestType>(c => c.DefaultRequests)
            .Select(c => c.DefaultRequests)
            .List();
        return null;
    }
}

生成的SQL只选择我想要所有子ID的父ID（这是参数）。

SELECT this_.Id as y0_
FROM   ClientContact this_
       inner join ClientContact_DefaultRequest defaultreq3_
         on this_.Id = defaultreq3_.ClientContactID
       inner join RequestType requesttyp1_
         on defaultreq3_.RequestTypeID = requesttyp1_.Id
WHERE  this_.Id = 313706 /* @p0 */

这有效，但它不是强类型（HQL）。

        var x = Session.CreateQuery("SELECT R.Id FROM ClientContact cc JOIN cc.DefaultRequests R WHERE cc.Id = :contactId")
            .SetParameter("contactId",ContactId)
            .List<int>();
        return x;

Answer 1

尝试使用别名，如：

ClientContact Cont = null;
RequestType Req = null;

var x = session.QueryOver<ClientContact>(() => Cont)
.Where(() => Cont.ID == ContactId)
.JoinAlias(() => Cont.DefaultRequests, ()=> Req, JoinType.LeftOuterJoin)
.Select(ignore => Req.Id) // <-- Select wants a parameter
.List<int>();

Answer 2

~~你必须扭转它。~~我相信Faber的答案也会奏效。所以你不必扭转局面。（但你可以。）

ClientContact cAlias = null;

var x = Session.QueryOver<RequestType>()
    .JoinAlias(rt => rt.ClientContacts, () => cAlias)
    .Where(() => cAlias.Id == ContactId)
    .Select(rt => rt.Id) // not sure what you want returned here, Id or the object)
    .List();

NHibernate从多个系列中选择

2 个答案: