Value objects are messing with Ef core linq query

Question

I have owned types in my Person class

public Name Firstname { get; protected set; }
public Name Lastname { get; protected set; }
public BirthDate BirthDate { get; protected set; }

i configured them (for EF Core 3.1) like this

builder.OwnsOne(x => x.Firstname).Property(n => n.Value).HasColumnName("Firstname");
builder.OwnsOne(x => x.Lastname).Property(n => n.Value).HasColumnName("Lastname");
builder.OwnsOne(x => x.BirthDate).Property(d => d.Value).HasColumnName("BirthDate");

and have query witch doesn't work

from b in context.People 
join p in context.RelatedPeople on b.Id equals p.PersonId into grouping
from p in grouping.DefaultIfEmpty()
group b by new { b.Personalnumber, p.PersonId } into g
select new { g.Key, count = g.Count() };

just throws weird exception

*Unhandled exception. System.InvalidCastException: Unable to cast object of type 'Microsoft.EntityFrameworkCore.Query.SqlExpressions.ColumnExpression' to type 'System.Linq.Expressions.ConstantExpression'.
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.RelationalProjectionBindingRemovingExpressionVisitor.GetProjectionIndex(ProjectionBindingExpression projectionBindingExpression)
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.RelationalProjectionBindingRemovingExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at System.Linq.Expressions.ExpressionVisitor.VisitBinary(BinaryExpression node)
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.RelationalProjectionBindingRemovingExpressionVisitor.VisitBinary(BinaryExpression binaryExpression)
   at System.Linq.Expressions.BinaryExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at System.Dynamic.Utils.ExpressionVisitorUtils.VisitBlockExpressions(ExpressionVisitor visitor, BlockExpression block)
   at System.Linq.Expressions.ExpressionVisitor.VisitBlock(BlockExpression node)
   at System.Linq.Expressions.BlockExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at System.Linq.Expressions.ExpressionVisitor.VisitLambda[T](Expression`1 node)
   at System.Linq.Expressions.Expression`1.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.RelationalProjectionBindingRemovingExpressionVisitor.Visit(Expression node, IReadOnlyList`1& projectionColumns)
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.VisitShapedQueryExpression(ShapedQueryExpression shapedQueryExpression)
   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.CreateQueryExecutor[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](Expression query, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult](IDatabase database, Expression query, IModel model, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass9_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQueryCore[TFunc](Object cacheKey, Func`1 compiler)
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func`1 compiler)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable`1.GetEnumerator()
   at ConsoleApp1.Program.Main(String[] args) in C:\Users\v.lashkhia\source\repos\TaskWebApi\ConsoleApp1\Program.cs:line 30*

if i change my ef core configuration and ignore this three value object, query starts working fine.

what am i missing? do i have bad configuration for owned types/value objects?

Answer 1

Your configuration for the owned types appears to be correct. You are right when you ignore the owned types there is no problem. How about side stepping the problem by changing your query to this:

from b in context.People select new {b.Id, b.PersonalNumber } into c
join p in context.RelatedPeople on c.Id equals p.PersonId into grouping
from p in grouping.DefaultIfEmpty()
group c by new { c.PersonalNumber, p.PersonId } into g
select new { g.Key, count = g.Count() };