LLBLGen Pro 2.6 Available

Version 2.6 of my favourite Object Relational Mapper, LLBLGen Pro, is now available.

The main addition to V2.6 is support for a full Linq provider, so writing queries in LLBLGen just became a lot easier. V2.6 also includes a new Prefetching API which I wrote during the 2.6 beta period, which Frans then included in the product.

For example, to eagerly load a Customer -> Orders relationship prior to v2.6, you'd have to do something like this:

EntityCollection<CustomerEntity> customers = new EntityCollection<CustomerEntity>(new CustomerEntityFactory());
 
PrefetchPath2 prefetcher = new PrefetchPath2(EntityType.Customer);
prefetcher.Add(CustomerEntity.PrefetchPathOrders);
 
using(DataAccessAdapter adapter = new DataAccessAdapter()) {
	adapter.FetchEntityCollection(customers, null, prefetcher);
}

Now, with the lambda prefetching API you can do this:

using(var adapter = new DataAccessAdapter()) {
	var linq = new LinqMetaData(adapter);
 
	var customers = (from c in linq.Customers select c)
				.WithPath(path => path.Prefetch(c => c.Orders));
 
}

Likewise, if you wanted to filter the prefetched orders (eg, only return orders costing more than £10) and prefetch each order's OrderDetail, you'd need to do something like this:

EntityCollection<CustomerEntity> customers = new EntityCollection<CustomerEntity>(new CustomerEntityFactory());
 
PrefetchPath2 prefetcher = new PrefetchPath2(EntityType.Customer);
prefetcher.Add(CustomerEntity.PrefetchPathOrders, 0, new PredicateExpression(OrderFields.TotalCost > 10))
	.SubPath.Add(OrderEntity.PrefetchPathOrderDetail);
 
using(DataAccessAdapter adapter = new DataAccessAdapter()) {
	adapter.FetchEntityCollection(customers, null, prefetcher);
}

...while now you can do this:

using(var adapter = new DataAccessAdapter()) {
	var linq = new LinqMetaData(adapter);
 
	var customers = (from c in linq.Customers select c)
				.WithPath(path =>
					path.Prefetch<OrderEntity>(c => c.Orders)
						.FilterOn(o => o.TotalCost > 10)
						.SubPath(orderPath => orderPath.Prefetch(o => o.OrderDetail))
				);
 
}

Lambdas rock :)

Written on June 8, 2008