score:2
Accepted answer
Try refactoring the IsNullOrEmpty condition like this:
return (from r in Repository.Query<Measurement>()
where
(string.IsNullOrEmpty(postalCode)
|| r.Postal.ToLowerInvariant() == postalCode.ToLowerInvariant()
)
&&
(string.IsNullOrEmpty(trait)
|| r.Trait.ToLowerInvariant() == trait.ToLowerInvariant()
)
select r).ToList();
That may cause LINQ to evaluate the IsNullOrEmpty before sending off the query. If not, you could precalculate them manually and put a couple boolean variables in their place.
score:1
Have you tried forcing the deferred execution by calling Repository.Query().ToList() before the where clauses? I noticed it looks like NHibernate is attempting to convert the string.IsNullOrEmpty() call into SQL syntax (and failing).
return (from r in Repository.Query<Measurement>().ToList()
where
r.Postal.ToLowerInvariant() ==
(string.IsNullOrEmpty(postalCode)
? r.Postal : postalCode).ToLowerInvariant()
&&
r.Trait.ToLowerInvariant() ==
(string.IsNullOrEmpty(trait)
? r.Trait : trait).ToLowerInvariant()
select r).ToList();
Source: stackoverflow.com
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