How to make Entity Framework cache some objects

Question

I'm using Entity Framework.

In my database are stored persons and country of their origins. When I'm loading a person object I wan't to know what is the place each person originates. Is there a way to cache list of countries so that there wouldn't be unnecessary requests.

Answer 1

I would cache that country list first and assign the appropriate country to each retrieved person. If you decide to also cache persons you should make them depend on the cached countries and invalidate them when you make any update to the countries/country list.

Answer 2

You could take a look at Jaroslaw Kowalski's excellent tracing and caching provider wrappers for Entity Framework.

Answer 3

As Luhmann has already said my mate Jarek has an excellent sample Caching provider for the Entity Framework. Which he talks about here.

However sometimes this approach is overkill, and I suspect that caching countries is a good example where the effort isn't worth it. It maybe better to implement some sort of ad-hoc caching.

If you try to do this the main problem you will run into is that an instance Entity Framework entity can only be attached to one ObjectContext at a time, which means if you are getting concurrent requests (like in a website) you will have problems is you just grab items from the cache and use them blindly.

What you need is a cloning cache, i.e. so when you grab something from the cache it clones them.

I put together a tip that illustrates how to do this Tip 14 - How to cache Entity Framework Reference Data

Hope this helps

Alex James

Entity Framework Team Microsoft.