01 July 2010

Simplify Entity Framework v4 models with complex types

One neat feature in Microsoft’s Entity Framework is support for complex types in the model. Complex types allow you to group together a bunch of properties in their own type and reuse that type from multiple entities. Complex types have been supported by Entity Framework from v1 although the v1 designer in Visual Studio 2008 didn’t support complex types, so until Visual Studio 2010 models using complex types had to be hand-edited in an XML editor.

The EFv4 designer in Visual Studio 2010 does support complex types, but it still involves a fair bit of manual work to define them, add them to entities and create mappings when working with multiple entities. There is a “Refactor into New Complex Type” feature in the VS2010 EF designer, but it unfortunately only works with one entity at a time.

To remedy this I looked into simplifying complex type creation and usage from multiple entity classes by adding a feature to Huagati DBML/EDMX Tools . The goal is to make generating and using complex types in EFv4 easier for EF models generated from existing databases.

EDMX Tools menu in VS2010

The new feature is quite simple, it lists all seemingly identical entity members in a model, ordered by number of occurrences in the model. A user can then select the members they want to generate a complex type from, and give the new type a name.

While selecting members, the add-in shows which model entities share the selected members. When adding a complex type this way, the underlying entities and the conceptual-to-storage mapping will be automatically updated to incorporate the complex types and map to the correct storage members.

Complex type generator dialog

The process can then be repeated as many times as wanted, leading to a less cluttered model diagram with less repeated-over-and-over-again member properties.

Entities without complex types
…entities without complex types…

Entities with complex types
…and the same entities after adding complex types…

This feature will be part of Huagati DBML/EDMX Tools version 1.90, together with some other new EFv4-specific features. The EFv4 specific features will only be available when using the add-in from Visual Studio 2010. Previously existing features will still work in both VS2008 and VS2010.

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