Lazy loading in Entity Framework is the default phenomenon that happens for loading and accessing the related entities. However, eager loading is referred to the practice of force-loading all these relations. I have come across the question of under what situation eager loading could be more beneficial than lazy loading. Asking this, because it is obvious that lazy loading is more resource friendly, and even if we use the
ToList() method, we can still take advantage of the lazy loading behavior. However, I thought maybe lazy loading increases the number of requests to the actual database and maybe that's why sometimes developers use the
Inlcude method to force-loading all relations. For example, when using the Visual Studio auto-scaffolding in MVC 5, the Index method that is automatically created in the controller always uses Eager Loading, and I've always had the question of why Microsoft uses Eager Loading by default in that case.
I would appreciate if someone explains to me under what situation eager loading would be more beneficial than lazy loading, and why do we use it at all while there's something more resource friendly as Lazy Loading.
I think it is good to categorize relations like this
When to use eager loading
When to use lazy loading
Note: like Transcendent said there may be disposal problem with lazy loading.
Eager Loading: Eager Loading helps you to load all your needed entities at once. i.e. related objects (child objects) are loaded automatically with its parent object.
When to use:
Lazy Loading: In case of lazy loading, related objects (child objects) are not loaded automatically with its parent object until they are requested. By default LINQ supports lazy loading.
When to use:
NOTE: Entity Framework supports three ways to load related data - eager loading, lazy loading and explicit loading.