Entity Framework - avoiding another query

Question

I have a requirement to only save data to a table in a database (I don't need to read it)

If the record already exists I want to update it otherwise I will add it. It usually exists.

My entity context might already hold the object .. if it does I want to find it and use it again without causing it to refresh from the database when I 'find' it

i.e. The context holds a collection of entities (rows of a database) I want to find an entity in the collection and only want the context to go to the database if entity is not in the collection. I don't care about the current values of the entity .. I just want to update them.

Hope this is clear ..... thanks

Answer 1

I may not be quite seeing the question, but I believe your looking for some sort of caching mechanism, I know for work we use devForces IdeaBlade which does the trick, however I believe you can create a simple caching mechanism custom to you needs.

http://blogs.msdn.com/b/jkowalski/archive/2009/06/11/tracing-and-caching-in-entity-framework-available-on-msdn-code-gallery.aspx

The bits on caching will be helpful, if this doesnt help tell me and I can dig a little deeper.

Answer 2

I believe you need to use GetObjectByKey() instead of using an ObjectQuery I believe an ObjectQuery always hits the backend datastore whatever it may be.

More Info here http://msdn.microsoft.com/en-us/library/system.data.objects.objectcontext.getobjectbykey.aspx