Orderby() not ordering numbers correctly c#
Int32.Parse is not supported by the LinqToSql translator. Convert.ToInt32 is supported. http://msdn.microsoft.com/en-us/library/sf1aw27b.aspx http://msdn.microsoft.com/en-us/library/bb882655.aspx
linq-to-sql
How to do a full outer join in Linq?
I think I have the answer here, which is not as elegant as I’d hoped, but it should do the trick: var studentIDs = StudentClasses.Select(sc => sc.StudentID) .Union(StudentTeachers.Select(st => st.StudentID); //.Distinct(); — Distinct not necessary after Union var q = from id in studentIDs join sc in StudentClasses on id equals sc.StudentID into jsc from … Read more
Explicit construction of entity type ‘###’ in query is not allowed.
Entities can be created outside of queries and inserted into the data store using a DataContext. You can then retrieve them using queries. However, you can’t create entities as part of a query.
maximum number of parameters in sql query
The limits are hard-coded: Parameters per stored procedure 2,100 Parameters per user-defined function 2,100 I wrote some code before that split the Contains query into batches and combined the results… see here for more.
Should I return IEnumerable or IQueryable from my DAL?
It depends on what behavior you want. Returning an IList<T> tells the caller that they’ve received all of the data they’ve requested Returning an IEnumerable<T> tells the caller that they’ll need to iterate over the result and it might be lazily loaded. Returning an IQueryable<T> tells the caller that the result is backed by a … Read more
Working around LinqToSQls “queries with local collections are not supported” exception
If Ids is a List, array or similar, L2S will translate into a contains. If Ids is a IQueryable, just turn it into a list before using it in the query. E.g.: List<int> listOfIDs = IDs.ToList(); var query = from st in dc.SomeTable where listOfIDs.Contains(st.ID) select …..
EntitySet – is there a sane reason that IList.Add doesn’t set assigned?
Interestingly, this has been identified for several versions now (you stated that a 3.5 issue was fixed in 4.0). Here is a post from 2007. The rest of the IList methods in 4.0 are correctly tied to the IList<T> methods. I think that there are 2 likely explanations (of the bug/feature variety): This is an … Read more
Which SQL Server field type is best for storing price values?
If you’re absolutely sure your numbers will always stay within the range of smallmoney, use that and you can save a few bytes. Otherwise, I would use money. But remember, storage is cheap these days. The extra 4 bytes over 100 million records is still less than half a GB. As @marc_s points out, however, … Read more
LINQ Between Operator
If you express it as a where clause it may just work out of the box with LINQ to SQL, if you can construct an appropriate expression. There may be a better way of doing this in terms of the expression trees – Marc Gravell may well be able to improve it – but it’s … Read more
Linq to SQL: how to aggregate without a group by?
This is what I found seems like you still have to do a group by…can just use constant: var orderTotals = from ord in dc.Orders group ord by 1 into og select new { prop1 = og.Sum(item=> item.Col1), prop2 = og.Sum(item => item.Col2), prop3 = og.Count(item => item.Col3) }; This produces the following SQL, which … Read more