DDD EF Repository

Question

With following DDD and the repository pattern, is it possible to return the aggregate root object with its child data already included instead of using lazy loading?

e.g. I have a warehouse entity as the aggregate root and it has a child object called location.

On the repository I have a method below to query the location Id but passes back the warehouse entity.

dim warehouse as Warehouse = warehouseRepository.FindByLocationId(Id as int32).
dim locationName as string = warehouse.location.where(function(x) x.Id = 1).firstordefault.name

When I use warehouse.location EF uses a proxy class to fire off another DB query to retrieve the location data. In my repository method FindByLocationId can I query the location DB table and pass back the warehouse entity with the location data included?

David Masters · Answer 1 · 2012-06-07T10:01:22.093

1

In general to stop lazy loading and proxies you can set the following properties on the Configuration property of your DbContext class. I tend to do this when overriding the OnModelCreating() method, so all my 'Setup' stuff is together.

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        Configuration.LazyLoadingEnabled = false;
        Configuration.ProxyCreationEnabled = false;


        base.OnModelCreating(modelBuilder);
    }

If you want to eagerly load a property you can use the Include() method:

var wareHouse = (from w in ctx.WareHouses.Include("location")
                select w).FirstOrDefault();

edited Jun 07 '12 at 10:01

answered Jun 07 '12 at 09:45

David Masters

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With the include statement it pulls back all the child records for warehouse, I only want to show 1 child record which i am querying for. I tried the following code but it still shows all the location records. Dim wareHouse = (From w In DataContextFactory.GetWMSDBContext.StockWarehouse Join sl In DataContextFactory.GetWMSDBContext.StockLocation On sl.WarehouseID Equals w.Id Where sl.Id = locationId Select w).FirstOrDefault() – user1180223 Jun 07 '12 at 10:09

score 0 · Answer 2 · answered Jun 07 '12 at 09:41

I presume you just want to use the include option in your query. http://msdn.microsoft.com/en-us/library/bb896272.aspx

So you'd have something like this:

var data = (from w in context.Warehouse
            .Include("Location")
            select w).FirstOrDefault();

DDD EF Repository

2 Answers2