ADO.NET Entity Framework

Karega Scott, Tuesday, July 29, 2008 @ 10:10 am

ADO.NET Entity Framework is an object relationship mapping (ORM) tool. It was designed to provide a layer of abstraction between the logical schema and concept schema of an application, and to decrease the amount code need for a data centric application.

Some benefits of the Entity framework:

• Data storage engine and schema independence: Due to the layer of abstraction between the logical and conceptual schema of your application, you no-longer need to know and hard cord the application to a specific data storage engine or schema.
• More expressive conceptual model: Entity types can inherit from other entity types and allows the creation of more complex types in addition to the standard scalar types support by the database.
• Access to multiple database system: Because the application is free from hard code data storage dependencies, the developer has the ability to access data from multiple storages using a consistent application object model
• LINQ: Language Integrated query support that offers compile time syntax checking for queries against the conceptual model.

The Entity Framework works by allow the developers to hand code or use code generation tools to create the XML metadata for the conceptual entity data model, a storage entity model, and a mapping specification between the two. The XML file created for the conceptual entity data model is then stored in the conceptual schema definition file (.csdl), the storage entity model is stored in the storage schema definition file (.ssdl), and mapping between the two in the mapping specification language file (.msl). These XML file are then loaded into the metadata workspace of the entity framework, and a set of classes are generated to allow the developer to work directly with the conceptual model and indirectly with the logical model.

Figure: ADO.NET Entity Framework Architecture

So with these benefits design and built directly into the the framework and the logical approach used by framework to interact with various data providers, some experts in entity-based applications and software architectures on the .NET platform still feel that the framework has some pretty large deficiencies.

They are concerned that the framework is...

• Inordinate focus on the data aspect of entities leads to degraded entity architectures
• Excess code needed to deal with lack of lazy loading
• Share, canonical model contradicts software best practices
• Lack of persistence ignorance causes business logic to be harder to read, write, and modify, causing development and maintenance costs to increase at an exaggerated rate.
• Excessive merge conflicts with source control in team environments.

Are these claim valid concerns to consider?

Sure, only if the framework is mature with several versions under its belt and its prohibits the productivity, maintainability and scalability of the application.

Isn't the right approach to software development to deliver a subset of the full feature set right the first time than try to deliver everything at once with massive issues that prevent the usability of the tool?

You decide...

Below are some useful references to get you going with Entity Framework.

Achieve Flexible Data Modeling With the Entity Framework
ADO.NET Entity Framework Pre-release documents
Microsoft ADO.NET Entity Framework Overview
ADO.NET Entity Framework Taking Some Heat
Programming Against the ADO.NET Entity Framework
ADO .NET Entity Framework Vote of No Confidence

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