DA LINQ and composite key joins

Data Abstract
1

Is this possible ? I can get single element joins to work, but I’m struggling to make composite field joins work - or find out if DA LINK supports it.

On the server side I have a linq local data adapter accessing my daSchema. It works until I try and use more than one element in the joins. For example in the “ff” code below , this builds but gives a “missing right parenthesis” error when the count causes the expression to be evaluated. The second “gg” example won’t even build - here I was trying to assign names to the keys as per http://msdn.microsoft.com/en-us/library/bb907099.aspx .

var ff := from part in self.fDataModule.DataAdapter.GetTable<Part> 
join sales in self.fDataModule.DataAdapter.GetTable<Sales> on new class (part.Name, part.Site) equals new class (sales.Name,sales.Site)
select new class (sales.Name);

var dx := ff.Count;

var gg := from nf in self.fDataModule.DataAdapter.GetTable<NodeForecast> 
join ns in self.fDataModule.DataAdapter.GetTable<NodeStructure> on new class (NT = nf.NodeType,GD =  nf.GID) equals new class (NT = ns.NodeType,GD = ns.GIDComponent)
select new class (ns.GIDComponent,nf.ForecastType);

var dy := gg.Count;
2

Hello.

Unfortunately, nowadays DA LINQ doesn’t support multiple key joins.

Thanks.

3

Ok. Is there a suggested “best practice” way of achieving the same end result, as we see using DA LINQ rigourously thoroughout our projects as a benefit (due to the strong typing and making good use of the schema).

Should we be looking at creating views for all such queries or perhaps the WHERE clause can be used to the same effect ? I’ve not looked at either possibility, but I’m open to ideas.

4

Hello.

Please consider to use Dynamic Where (see it at http://wiki.remobjects.com/wiki/Dynamic_Where) in your project. Also, please take a look at RemObjects DataAbstract example “Dynamic Where” (see it at “C:\Users\Public\Documents\RemObjects Samples\Data Abstract for .NET\C#\Dynamic Where”). It shows using Dynamic Where in action.

Thanks