Archives
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Modifying Self Tracking Entity on the server
Suppose you are working with a console application on the server and you have created an entity data model with applicant entity as shown below.
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Loading recursive queries
Entity framework supports self referencing entity where an entity has a a reference to itself. A common example of that would be a category with subcategories. In the database you would typically see a category table with a ParentCategoryId column which represents the parent category of the current category. Figure below shows the Category table in the database.
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Using Self Tracking Entity to retrieve and update
In this tutorial I will explain how to use Self Tracking Entity to retrieve entities from a WCF service, modify the object graph on the client side and then send those changes back to the server in a clean way.
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Returning Maximum value from 1-to-many association
Today I was working with two entities and i wanted to return the maximum value in the many table for each record in the parent table. There are several approaches to returning the desired data but since my tables had lots of records i wanted to explore different queries and compare which one generates a better sql and gives me better performance.
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Registering with AssociationChanged event on POCO with change tracking proxy
Entity Framework 4.0 allows you to use POCO objects for your entities defined on the model. Suppose one of the POCO entity has a collection property and you want to be notified when a new entity is added or removed from the collection. How do we get notified when the collection is changed? Well if your poco objects supports change tracking proxy, you can be assured that Entity Framework will initialize your collection to EntityCollection. You can use EntityCollection’s AssociationChanged event to find out what got added or removed. EntityCollection has been around since version 1 and it is currently the collection that is used if you use the default code generation. Some of the benefit of using EntityCollection includes.
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Placing Model in separate Assembly
Today, I was cruising the forum and i ran across an interesting post where the poster wanted to place the model and ObjectContext in different assemblies. Imagine you have a customer table and you created the Entity Data Model with Customer entity. You wanted your tiers to be as follows