Entity Framework Advanced Topics and Best Practices

1. Entity Framework
Session #3 : advanced topics & best practices
By: Usama Nada.
Lead Software Engineer

2. Agenda
• Eager Loading vs Lazy Loading
• Asynchronous query and save
• Optimistic Concurrency using RowVersion
• Best Practices in Entity Framework Usage

3. Eager Loading vs Lazy Loading
• Lazy Loading:
Related objects (child objects) are not loaded automatically with its parent object until
they are requested.
• Eager Loading:
Forcing Child related objects to load with its parent

4. Asynchronous query and save
• Non blocking calls to the data layer is a great way to increase the scalability
of your system.
• Frees up the worker thread to accept another request while work is being
done in the background

5. Optimistic Concurrency
• The pessimistic approach is a user thinking "I'm sure someone will try to
update this row at the same time as I will, so I better ask the database server
to not let anyone touch it until I'm done with it.“
• The optimistic approach is a user thinking "I'm sure it's all good and there
will be no conflicts, so I'm just going to remember this row to double-check
later, but I'll let the database server do whatever it wants with the row."

6. Best Practices
• Never Use Singleton DbContext
• Update to the latest version using NuGet Package manager
• If you face performance issue of complex queries, you have the ability to use stored
procedures.
• Minimize roundtrips to database
• Avoid fetching all the fields if not required.
• When object cache has very large amount of entities, it causes performance issues.
• Disabling change tracking to reduce state management overhead
• Split Large models for better designer and source control performance
• Choose appropriate Collection for data manipulation IEnumerableVS IQueryable,

7. General Best Practices
• Limit your result set using reasonable limits using paging. Never Load all table
entities (unless you have good reason for that)
• Cache Expensive result sets:
• Take long time in execution
• Short execution time bug get called too many times like lookups
• Embrace Asynchronous Programming techniques
• Use Fast Serializers
• What Else ??

8. Resources
• Performance Considerations for Entity Framework 4, 5, and 6:
http://msdn.microsoft.com/en-us/data/hh949853.aspx
• Why you should use async tasks in .NET 4.5 and Entity Framework 6:
http://www.itworld.com/development/405462/why-you-should-use-async-tasks-net-
45-and-entity-framework-6
• DbContext in Singleton: http://www.britishdeveloper.co.uk/2011/03/dont-use-singleton-
datacontexts-entity.html