Question

An Activity occurs at a location on a specific date, but each activity may be repeated at the same or different locations on different dates. I have created an entity framework model, and wish to populate it with relevant Activities which occur between two dates, ordered by the locations distance from a specified location.

I therefore have a the following tables:

Activity (A)

Occurrence (O)

Location (L)

With relationships as follows:

A 1-n O n-1 L

I am having some difficulty in doing this using linq to entities, but am sure that I can achieve it in a stored procedure.

Is this something that I should be able to do using Linq or is it too complex a problem for Linq to create the Sql? Any pointers about writing the Linq query would be appreciated, if it is something that it should be able to do.

Answer 1

var query = from occurrence in occurrenceList
            join activity in activityList on occurrence.ActivityID equals activity.ID
            join location in locationList on occurrence.LocationID equals location.ID
            let distance = CLocation.Distance (referenceLocation, location)
            orderby distance, activity.Name
            where start <= occurrence.Date && occurrence.Date <= end
            select new
            {
                ActivityName = activity.Name, 
                LocationName = location.Name,
                Distance = distance,
                Date = occurrence.Date
            };