How can I do the following using QueryOver and no Formula Fields.
I have the following parent/child relationship
public class Club {
public string Name {get; set;}
public IList<Membership> Memberships {get; set;}
}
public class Membership {
public boolean Cancelled {get; set;}
public Club Club {get; set;}
}
I have the following query that returns 15 Clubs and transforms the results to a DTO, I need to add to this query a RowCount of Memberships that belong to each club and that are not Cancelled.
IEnumerable<ClubIndexViewModelLineSummary> results = _querySession.QueryOver<Club>()
.OrderBy(c => c.IsActive).Desc
.OrderBy(c => c.Name).Asc
.SelectList(list => list
.Select(c => c.Id).WithAlias(() => sum.Id)
.Select(c => c.Name).WithAlias(() => sum.Name)
.Select(c => c.IsActive).WithAlias(() => sum.IsActive)
.Select(c => c.NumberOfWeeks).WithAlias(() => sum.NumberOfWeeks))
.TransformUsing(Transformers.AliasToBean<ClubIndexViewModelLineSummary>())
.Skip(start)
.Take(15)
.Future<ClubIndexViewModelLineSummary>();
After some more research, this is the resulting query that works:
Club clubAlias = null;
IEnumerable<ClubIndexViewModelLineSummary> results =
_querySession.QueryOver<Club>(() => clubAlias)
.OrderBy(c => c.IsActive).Desc
.OrderBy(c => c.Name).Asc
.SelectList(list => list
.Select(c => c.Id).WithAlias(() => sum.Id)
.Select(c => c.Name).WithAlias(() => sum.Name)
.Select(c => c.IsActive).WithAlias(() => sum.IsActive)
.Select(c => c.NumberOfWeeks).WithAlias(() => sum.NumberOfWeeks)
.SelectSubQuery
(
QueryOver.Of<ClubMembership>()
.Where(c => c.Canceled == false)
.And(c=> c.Club.Id == clubAlias.Id)
.ToRowCountQuery()
).WithAlias(()=> sum.ActiveMembers))
.TransformUsing(Transformers.AliasToBean<ClubIndexViewModelLineSummary>())
.Skip(start)
.Take(15)
.Future<ClubIndexViewModelLineSummary>();
来源:https://stackoverflow.com/questions/6333217/get-children-count-with-restrictions-using-queryover-on-nhibernate