Possible to use Tables of same type in Linq to SQL?

Question

Lets say I've got an object model, where I have many collections of the same type.

For example something like

class StockMarketData {
  List<SummaryData> WeeklySummary;
  List<SummaryData> MonthlySummary;
}

class SummaryData {
  DateTime DateTime {get; set;}
  double Value {get; set;}
}

Those lists will map onto database tables.

If you actually use L2S to generate a model from the database you will get something like:

class StockMarketData {
      List<WeeklySummaryData> WeeklySummary;
      List<MonthlySummaryData> MonthlySummary;
    }

Even though WeeklySummaryData and MonthlySummaryData have the same shape.

Is it possible for Linq to SQL to create tables from a database of summary data, but get each table to contain the same type (such as shown in the top example).

Answer 1

This scenario is supported in the designer in the entity framework, but not in the designer (dbml) in linq to sql.

To go down the more manual path, create a class that is not a database entity, called SummaryData and populate the class when you Select either the WeeklySummaryData or MonthlySummaryData. You can then expose properties like this off the DataContext partial class (View Code on the dbml):

IQueryable<SummaryData> WeeklySummary
{
    get
    {
        from wsd in WeeklySummaryData
        select new SummaryData { DateTime = wsd.DateTime, Value = wsd.Value }
    }
}

IQueryable<SummaryData> WeeklySummary
{
    get
    {
        from msd in MonthlySummaryData
        select new SummaryData { DateTime = msd .DateTime, Value = msd.Value }
    }
}