Chris wrote:
Trying to get my head around linq. Here is what I have:
Tables:
OrderHeader
OrderLineItem
OrderSubLineItem
The result set I need is:
OrderHeader.Description, Count(OrderSubLineItem) as CountAllItems
What I wanted to do is
var Result = from Item in DB.OrderHeader
where Item.OrderHeadID = ID
select new {Item.Description,
Item.OrderLineItem.OrderSubLineItem.Count}
I can't drill down from OrderLineItem to OrderSubLineItem though.
If you need a given resultset, it's not about what you want to do, it's
about what you have to do. You can't 'drill down' to them as that
requires an m:1/1:1 relationship, and OrderLineItem has a 1:n
relationship with OrderSubLineItem.
You could try:
var q = from osli in DB.OrderSubLineItem
group osli by osli.OrderLineItem.OrderHeader.Description into g
select new { g.Key, CountAllItems = g.Count() };
Now you can drill 'up' as all relationships are m:1.
You can also create a subquery inside the projection, which is
effectively a scalar, though that leads to less efficient SQL.
I am guaranteed that all LineItems have SubLineItems.
Also, I would like to return a dictonary of this and seem to have
having problems doing the ToDicontary when I do a select new at the
bottom of my LINQ.
the select new creates an anonymous type. The ToDictionary() method
will return a dictionary with values of that anonymous type. This means
that you should do:
var dict = q.ToDictionary(v=>v.Key);
FB
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