LINQ Self Projection
Joined: 04-Jun-2008
Joined: 04-Jun-2008
Joined: 04-Jun-2008
Joined: 04-Jun-2008
Joined: 04-Jun-2008
Joined: 04-Jun-2008
I can reproduce it with this query in VB.NET (same query, ported to VB.NET)
<Test()> _
Public Sub GetCustomerIdsWithOrdersInAnonymousType()
Using adapter As New DataAccessAdapter()
Dim metaData As New LinqMetaData(adapter)
Dim q = From c In metaData.Customer _
Select c.CustomerId, c.CompanyName, Orders = metaData.Order.Where(Function(o) o.CustomerId = c.CustomerId).Take(5)
Dim count As Integer = 0
For Each v In q
count += 1
If (v.CompanyName = "FISSA Fabrica Inter. Salchichas S.A.") OrElse (v.CompanyName = "Paris spécialités") Then
' no orders
Continue For
End If
Assert.IsTrue(v.Orders.Count() > 0)
Assert.IsTrue(v.Orders.Count() <= 5)
Next
Assert.AreEqual(91, count)
End Using
End Sub
gives:
failed: SD.LLBLGen.Pro.ORMSupportClasses.ORMQueryConstructionException : A nested query in the projection has no correlation filter to tie its set to the containing parent row. Please add a correlation filter to the where clause of this query to tie the nested query to the parent. C:\Myprojects\VS.NET Projects\LLBLGen Pro v2.0\LinqSupport\LinqSupportClasses .NET 3.5\ExpressionClasses\QueryExpression.cs(231,0): at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionClasses.QueryExpression.FindCorrelationFilterPredicates(IElementCreatorCore generatedCodeElementCreator, MappingTracker trackedMappings) etc.
expression:
value(SD.LLBLGen.Pro.LinqSupportClasses.DataSource2`1[NW26.Adapter.EntityClasses.CustomerEntity]).Select(c => new VB$AnonymousType_4`3(CustomerId = c.CustomerId, CompanyName = c.CompanyName, Orders = Convert(value(VBTestQueries.DynamicListFetches+_Closure$__1).$VB$Local_metaData.Order).Where(o => (CompareString(o.CustomerId, c.CustomerId, False) = 0)).Take(5)))
(ironically, without the select(i=i) 
)
So now that we've a repro, we can try to fix it. We'll look into it and get back to you a.s.a.p.
// C#
value(SD.LLBLGen.Pro.LinqSupportClasses.DataSource2`1[NW26.Adapter.EntityClasses.CustomerEntity])
.Select(c => new <>f__AnonymousTypeb0`3(CustomerId = c.CustomerId, CompanyName = c.CompanyName,
Orders = value(LinqTester.AdapterTests.DynamicListFetches+<>c__DisplayClass20).metaData.Order
.Where(o => (o.CustomerId = c.CustomerId)).Select(i => i).Take(5)))
// VB.NET
value(SD.LLBLGen.Pro.LinqSupportClasses.DataSource2`1[NW26.Adapter.EntityClasses.CustomerEntity])
.Select(c => new VB$AnonymousType_4`3(CustomerId = c.CustomerId, CompanyName = c.CompanyName,
Orders = Convert(value(VBTestQueries.DynamicListFetches+_Closure$__1).$VB$Local_metaData.Order)
.Where(o => (CompareString(o.CustomerId, c.CustomerId, False) = 0)).Take(5)))
It's clear why this is: the VB.NET part compares correlated inner query with the outer query using a function call which is executed inside the DB. Normally, this isn't doable, as the database function performs the correlation but it's unclear on what ground (and it can't be executed in-memory to bind outer to inner).
A special case code path could solve this (by hard-coded checks for Compare* methods (vb specific) which then convert these back to a normal binary expression, however, it's also solveable inside the query. I'll look at your C# query and will post the workaround.
(edit) not possible as you fetch a 1:n relationship in the projection of a fetch of the 'n' side (so a m:1 projection. Lots of redundant data!). So there you indeed need the manually specified correlated filter. 
Looking into a solution for this. It might be that we need till tomorrow (friday) before a fix is posted.
Joined: 04-Jun-2008
Joined: 04-Jun-2008
JeffN825 wrote:
Thank you Frans. Your support of the product has never been anything short of outstanding.
JeffN825 wrote:
When you say VB .NET query do you mean you want the whole query in VB .NET?
the full query itself is in a C# compiled assembly (so the big part has never been in VB). It's just the caller that uses it in a separate assembly that's VB.
I found it. I compared the massive expressions with each other and they're completely the same except the Select(i=>i) on the outside as you already suggested.
So doing:
[Test]
public void GetCustomerIdsWithOrdersInAnonymousType()
{
using(DataAccessAdapter adapter = new DataAccessAdapter())
{
LinqMetaData metaData = new LinqMetaData(adapter);
var q = from c in metaData.Customer
select new {
c.CustomerId,
c.CompanyName,
Orders = metaData.Order.Where(o => o.CustomerId == c.CustomerId)
};
q = q.Select(i => i).Take(5);
int count = 0;
foreach(var v in q)
{
count++;
if((v.CompanyName == "FISSA Fabrica Inter. Salchichas S.A.") || (v.CompanyName == "Paris spécialités"))
{
// no orders
continue;
}
Assert.IsTrue(v.Orders.Count() > 0);
Assert.IsTrue(v.Orders.Count()<=5);
}
Assert.AreEqual(91, count);
}
}
indeed gives the same problem in C#, simply because the nested query containing projection isn't the outer projection (so it can't merge the queries).
VB.NET inserts the .Select(i=>i) as there's no Select in the C# expression (as the projection is placed inside the Join's expression), and thus this gives the problem. So all in all a not that common problem but nasty if you run into it.
We'll address these two problems and will release a new build for you a.s.a.p. (but it will be tomorrow (friday) before we'll have it fixed.
Joined: 04-Jun-2008
JeffN825 wrote:
Thank you! We'll try it out right away.
Your responsiveness fixing these kinds of things speaks worlds.
Thank you Jeff
Just making sure our support quality is above the level of the competition