Unfortunately it doesn't seem to work the moment you want to add any kind of
order by clause relating to BarCount.

James

On 18 May 2010 14:22, Diego Mijelshon <[email protected]> wrote:

> Yes, it works.
>
>    Diego
>
>
>
> On Tue, May 18, 2010 at 09:27, Mohamed Meligy <[email protected]>wrote:
>
>> Does this work on NH trunk LINQ provider?
>>
>> var query = from foo in session.Query<Foo>() select new FooDTO {Foo = foo,
>> BarCount = foo.Bars.Count()};
>>
>> I think typically the problem for this might be the "IEnumerable" type of
>> Bars. Not sure if NH implementation can handle such query though, but it's
>> worth trying.
>>
>> --
>> Mohamed Meligy
>> Senior Developer, Team Lead Backup (.Net Technologies - TDG -
>> Applications)
>> Injazat Data Systems
>> P.O. Box: 8230 Abu Dhabi, UAE.
>>
>> Phone:  +971 2 6992700
>> Direct:   +971 2 4045385
>> Mobile:  +971 50 2623624, +971 55 2017 621
>>
>> E-mail: [email protected]
>> Weblog: http://gurustop.net
>>
>>
>>
>> On Tue, May 18, 2010 at 2:50 PM, nadav s <[email protected]> wrote:
>>
>>> may be write the sql thisway:
>>> select foo.*, (select count(*) from bars where bars.fooid = foo.id)
>>> barsCount
>>> from foo
>>>
>>> The folowing code executes the query and get the results you wanted
>>>
>>>            IClassMetadata deptMetaData =
>>>                     sessionFactory.GetClassMetadata(typeof(Department));
>>>            string[] propertyNames = deptMetaData.PropertyNames;
>>>
>>>
>>>             ICriteria c = s.CreateCriteria<Department>("d");
>>>             DetachedCriteria dc = DetachedCriteria.For<Employee>("e");
>>>             dc.Add(Restrictions.EqProperty("d.id", "e.Department.id"));
>>>             dc.SetProjection(Projections.Count("id"));
>>>
>>>             ProjectionList projList = Projections.ProjectionList();
>>>             foreach (string propName in propertyNames)
>>>             {
>>>                 projList.Add(Projections.Property(propName));
>>>             }
>>>             projList.Add(Projections.Alias(Projections.SubQuery(dc),
>>> "counting"));
>>>             c.SetProjection(projList);
>>>             c.SetMaxResults(1);
>>>             IList results = c.List();
>>>    .
>>> You extract the building of the projection list of all the properties of
>>> the class to an a utils class like ProjectionList
>>> MyProjections.AllProperties(Type type)
>>> for creating the projections for all the properties of the class
>>>
>>> i think the proper way to read the results is with a custom result
>>> transformer but i'm not sure
>>>
>>>
>>> On Tue, May 18, 2010 at 12:46 PM, James Crowley <[email protected]
>>> > wrote:
>>>
>>>> I too would be interested to get people's suggestions on how best to do
>>>> this? You can't seem to get the AliasToBean transformer to deal with the
>>>> fact we want to set properties on a child property of the DTO either?
>>>>
>>>> Would appreciate any pointers you guys have!
>>>>
>>>> Thanks
>>>>
>>>> James
>>>>
>>>>
>>>> On 10 May 2010 13:17, kaa <[email protected]> wrote:
>>>>
>>>>> Say I have two entities Foo and Bar where Foo has-many Bar's,
>>>>>
>>>>> class Foo {
>>>>>   int ImportantNumber { get; set; }
>>>>>   IEnumerable<Bar> Bars { get; set; }
>>>>> }
>>>>>
>>>>> class FooDTO {
>>>>>   Foo Foo { get; set; }
>>>>>   int BarCount { get; set; }
>>>>> }
>>>>>
>>>>> How can I efficiently sum up the number of Bars per Foo in a DTO using
>>>>> a single query, preferrably only with the Criteria interface.
>>>>> I have tried any number of ways to get the original entity out of a
>>>>> query with ´SetProjection´ but no luck. The current theory is to do
>>>>> something like
>>>>>
>>>>> SELECT
>>>>>   Foo.*, BarCounts.counts
>>>>> FROM
>>>>>   Foo LEFT JOIN
>>>>>     ( SELECT fooId, COUNT(*) as counts FROM Bar    ON
>>>>> Foo.id=BarCounts.fooId
>>>>>
>>>>> but with Criterias, and I just can't seem to figure out how.
>>>>>
>>>>> I posted the same question over at stackoverflow.com where I got the
>>>>> following suggestion, using HQL,
>>>>>
>>>>> var fooDTOs = session.CreateQuery(@"
>>>>>  select foo as Foo,
>>>>>     count(elements(foo.Bars)) as BarCount
>>>>>  from Foo foo
>>>>>   group by foo.id, foo.ImportantNumber")
>>>>>  .SetResultTransformer(Transformers.AliasToBean<FooDTO>())
>>>>>  .List<FooDTO>();
>>>>>
>>>>> My problem with this is that my actual Foo has a lot of properties and
>>>>> maintaining that is a bit of a worry. Can I somehow write something
>>>>> closer to my original SQL query?
>>>>>
>>>>> Any help would be appreciated.
>>>>>
>>>>> --
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>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> ---
>>>> James Crowley
>>>> CEO, developerFusion - the global developer community -
>>>> http://www.developerfusion.com/
>>>> CTO, TechEye - all the technology news unfit for print -
>>>> http://www.techeye.net/
>>>>
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---
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