sdanyliv
commented
6 months ago Cte implementation in linq2db (should be fxed in upcoming version 6) do not support inheritance. As a workaround you can return PK and materialize joined values. Your query also totally incorrect and I have prepared correct version:
Define intermediate class
class StorageItemCte
{
public Guid Id { get; set; }
}var guid = Guid.Parse("84eb9daa-fbcf-464a-a9da-9b1fbc599a72");
using var db = _dbContext.CreateLinqToDBConnection();
var cteQuery = db.GetCte<StorageItemCte>(storageItems =>
{
return
(
from si in _dbContext.StorageItems
where si.Id == guid
select new StorageItemCte { Id = si.Id }
)
.Concat
(
from si in _dbContext.StorageItems
from cte in storageItems.InnerJoin(cte => cte.Id == si.ParentId)
select new StorageItemCte { Id = si.Id }
)
});
var resultQuery =
from cte in cteQuery
from si in _dbContext.StorageItems.InnerJoin(si => si.Id == cte.Id)
select si;
var res = await result.ToListAsyncLinqToDB();
neistow
I'm trying to do the following query with linq2db and ef core:
Here's my dbcontext configuration:
Here's translated version using linq2db:
Exception I'm getting:
I did a little bit of investigation and found out that this line errors, because it can't find memberinfo that has the same declaring type parent that union parameter type (which is StorageItem) has. Basically it fails because StorageItem is not convertible to StorageFolder, which is kind of logical, but EF is able to create concrete types and cast them to base class while querying. Not sure if it's a bug or just linq2db doesn't support TPH with recursive CTE