LINQ do NHibernate: suma kwot

Question

Having podmiotów NHibernate:

Company, Invoice i InvoiceLine który ma właściwość dziesiętną Price.

A Company ma kolekcję typu Invoice, a Invoice ma kolekcję typu InvoiceLine.

W jaki sposób mogę uzyskać sumę wszystkich cen, które należą do wierszy faktury, które należą do faktur określonej firmy określonej przez id?

Próbowałem napisać kwerendę tak:

session 
    .Query<InvoiceLine>() 
    .Where(invoiceLine => invoiceLine.Invoice.Company.Id == companyId) 
    .Sum(invoiceLine => invoiceLine.Price); 

ale zgłasza wyjątek:

NHibernate.Exceptions.GenericADOException 
"Could not execute query[SQL: SQL not available]" 

    at NHibernate.Impl.SessionImpl.List(IQueryExpression queryExpression, QueryParameters queryParameters, IList results) 
    at NHibernate.Impl.AbstractSessionImpl.List(IQueryExpression queryExpression, QueryParameters parameters) 
    at NHibernate.Impl.ExpressionQueryImpl.List() 
    at NHibernate.Linq.DefaultQueryProvider.ExecuteQuery(NhLinqExpression nhLinqExpression, IQuery query, NhLinqExpression nhQuery) 
    at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression) 
    at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression) 
    at System.Linq.Queryable.Sum[TSource](IQueryable`1 source, Expression`1 selector) 

wewnętrzny wyjątek:

System.ArgumentNullException 
"Value cannot be null.\r\nParameter name: item" 

    at System.ThrowHelper.IfNullAndNullsAreIllegalThenThrow[T](Object value, ExceptionArgument argName) 
    at System.Collections.Generic.List`1.System.Collections.IList.Add(Object item) 
    at NHibernate.Util.ArrayHelper.<>c__DisplayClass2.<AddAll>b__0() 
    at NHibernate.Util.ArrayHelper.AddAll(IList to, IList from) 
    at NHibernate.Engine.Query.HQLQueryPlan.PerformList(QueryParameters queryParameters, ISessionImplementor session, IList results) 
    at NHibernate.Impl.SessionImpl.List(IQueryExpression queryExpression, QueryParameters queryParameters, IList results) 

Może to mieć coś wspólnego z podsumowując puste kolekcje, ale nie jestem pewien, jak to naprawić.

Answer 1

Spróbuj odlewania Price do pustych decimal ...

.Sum(invoiceLine => (decimal?)invoiceLine.Price) ?? 0; 

Rezultatem jest wyraźnie decimal?

Answer 2

session 
    .Query<InvoiceLine>() 
    .Where(invoiceLine => invoiceLine.Invoice.Company.Id == companyId && invoiceLine.Price != null) 
    .Sum(invoiceLine => (decimal)invoiceLine.Price); 

Answer 3

Rozwiązanie oznaczone jako odpowiedź nie ratować problem dla mnie. Zamiast GenericAdoException dostałem wyjątek InvalidOperationException z poniższym stosem.

Proponowane rozwiązanie tutaj Linq: select property collection jest właściwym rozwiązaniem dla mnie.

Une erreur inattendue de type InvalidOperationException s'est produite sur le serveur 
System.InvalidOperationException: Code supposed to be unreachable 
    à System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack) 
    à System.Linq.Expressions.Compiler.StackSpiller.RewriteUnaryExpression(Expression expr, Stack stack) 
    à System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack) 
    à System.Linq.Expressions.Compiler.StackSpiller.RewriteExpressionFreeTemps(Expression expression, Stack stack) 
    à System.Linq.Expressions.Compiler.StackSpiller.Rewrite[T](Expression`1 lambda) 
    à System.Linq.Expressions.Expression`1.Accept(StackSpiller spiller) 
    à System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda, DebugInfoGenerator debugInfoGenerator) 
    à System.Linq.Expressions.Expression`1.Compile() 
    à NHibernate.Linq.ExpressionToHqlTranslationResults.MergeLambdasAndCompile[TDelegate](IList`1 itemTransformers) 
    à NHibernate.Linq.ExpressionToHqlTranslationResults..ctor(HqlTreeNode statement, IList`1 itemTransformers, IList`1 listTransformers, IList`1 postExecuteTransformers, List`1 additionalCriteria) 
    à NHibernate.Linq.IntermediateHqlTree.GetTranslation() 
    à NHibernate.Linq.Visitors.QueryModelVisitor.GenerateHqlQuery(QueryModel queryModel, VisitorParameters parameters, Boolean root) 
    à NHibernate.Linq.NhLinqExpression.Translate(ISessionFactoryImplementor sessionFactory, Boolean filter) 
    à NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory) 
    à NHibernate.Engine.Query.QueryExpressionPlan.CreateTranslators(IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory) 
    à NHibernate.Engine.Query.QueryExpressionPlan..ctor(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory) 
    à NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters) 
    à NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow) 
    à NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression queryExpression) 
    à NHibernate.Linq.DefaultQueryProvider.PrepareQuery(Expression expression, IQuery& query, NhLinqExpression& nhQuery) 
    à NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression) 
    à NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression) 
    à System.Linq.Queryable.Sum[TSource](IQueryable`1 source, Expression`1 selector) 
    à Secib.Server.Services.ReglementService.GetRegleTtc(FactureView facture) dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Services\ReglementService.cs:ligne 425 
    à Secib.Server.Services.ReglementService.DoesMontantSoldeFacture(FactureView facture, Decimal montantImpute) dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Services\ReglementService.cs:ligne 391 
    à Secib.Server.Services.ReglementService.DispatcheMontantImpute(Reglement reglement, ReglementFactureCompactDto factureDto) dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Services\ReglementService.cs:ligne 236 
    à Secib.Server.Services.ReglementService.SaveReglement(Reglement reglement, IList`1 factures) dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Services\ReglementService.cs:ligne 197 
    à Secib.Server.Controllers.ReglementController.<SaveReglement>z__OriginalMethod() dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Controllers\ReglementController.cs:ligne 141 
    à Secib.Server.Controllers.ReglementController.<SaveReglement>c__Binding.Invoke(Object& instance, Arguments arguments, Object aspectArgs) dans :ligne 0 
    à PostSharp.Aspects.Internals.MethodInterceptionArgsImpl`1.Proceed() 
    à Secib.Server.Aspects.TransactionAspect.OnInvoke(MethodInterceptionArgs args) dans x:\Sources\Next\Alpha\SecibNext\Secib.Server\Aspects\TransactionAspect.cs:ligne 32