I'm struggling to get my head around how best to eager load entities, and how to assign relationships when creating new entities. I'm using EF5 POCO, by the way.

I'm retreiving a large hierarchy of entities from a database, representing chemical analysis results. As a simple example I have an "AnalysisResult" entity with two generated properties that relate it to a "ChemicalElement" entity - ChemicalElement and ChemicalElementId. Standard stuff so far.

I started out by retrieving my AnalysisResults from the database and eager loading the related ChemicalElements using the .Include LINQ statement, meaning I could access a result's chemical element simply via AnalysisResult.ChemicalElement. This was fine for results loaded from the database, but what if I wanted to create a new AnalysisResult - how would I get the ChemicalElement entity that I wanted to assign to it?

As chemical elements never change, I decided to treat them as "reference/lookup data", so I dropped the eager loading, and I now retrieve all ChemicalElements into a separate collection that I can refer to whenever I need. The downside of dropping eager loading is that an AnalysisResult loaded from the database has a null .ChemicalElement property, so I have to use its .ChemicalElementId property to lookup the ChemicalElement entity in my "reference collection".

Have I overcomplicated the solution? Should I keep the idea of the ChemicalElement "reference collection" but also eager load them when retrieving existing AnalysisResults? It seems wasteful to (potentially) retrieve them twice - once when I retrieve them all, and again when eager loading during the AnalysisResults retrieval.

1 Answer 1


Deciding if you should load some information (eager or lazy) depends mostly on your usage patterns.

I'm guessing the displaying the chemical information is the main scope of your application.

On a previous application that worked with cars we cached properties like car color and body types. We made the connection with the data coming from the database in the view (using controls/helpers).

This made sure that we didn't overburden the database with heavy handed joins.

  • +1 for usage patterns. Also look at your classes of user, will they all view the data the same way?
    – ozz
    Apr 5, 2013 at 10:48

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