public static IFutureValue <TValue> FutureValue <T, TValue>(this IQueryOver <T> query, IDatabaseProvider databaseProvider)
{
if (databaseProvider.SupportFuture)
{
return(query.FutureValue <TValue>());
}
return(new FunnelWebFutureValue <TValue>(query.SingleOrDefault <TValue>()));
}
private int GetCount(IQueryOver <AggregateNodeStatus, AggregateNodeStatus> aggQuery, bool requiresLoadingIds)
{
if (requiresLoadingIds)
{
// We can't do a count in the db engine and must load the distinct Ids instead
var ids = aggQuery
.Select(Projections.Distinct(Projections.Property <AggregateNodeStatus>(x => x.Node.Id)))
.Future <Guid>();
return(ids.Distinct().Count());
}
int count;
if (Helper.SupportsCountDistinct())
{
// Set the aggregate to return a count of the distinct NodeIds
aggQuery = aggQuery.Select(Projections.CountDistinct <AggregateNodeStatus>(x => x.Node.Id));
count = aggQuery.FutureValue <int>().Value;
}
else
{
// SqlCe doesn't support distinct in aggregates, so create a subquery
// The ideal subquery for SqlCe would be
// select count(*) from (select distinct NodeId ...)
// However you can't select from a derived table in NH so we have to do a
// select count(*) where exists (select distinct NodeId .. where versionid & statusid match)
// We could revert back to the ideal version if we used manual Sql concatenation
// Create the distinct NodeId projection
aggQuery = aggQuery.Select(Projections.Distinct(Projections.Property <AggregateNodeStatus>(x => x.Node.Id)));
// Add some criteria to the inner aggregate query to tie it to the new outer one we'll create for the count
AggregateNodeStatus outer = null;
aggQuery = aggQuery
.Where(x => x.NodeVersion == outer.NodeVersion)
.And(x => x.StatusType == outer.StatusType);
var outerQuery = Helper.NhSession.QueryOver(() => outer)
.Select(Projections.Count <AggregateNodeStatus>(x => x.Node.Id))
.WithSubquery.WhereExists((QueryOver <AggregateNodeStatus>)aggQuery);
count = outerQuery.FutureValue <int>().Value;
}
return(count);
}
public TRoot SingleOrDefault()
{
Build();
return(MainQuery.FutureValue().Value);
}