How to generate Views using databasefirst and entity framework? - entity-framework

Question

I've been given a Visual Studio solution to get up and running again for development. The project uses Entity Framework database first. When I generate model from database, the sql wants to convert all of the views into tables. I know views should be avoided with EF, but what is the best way to correct this issue given that the developer no longer works for us?
Thanks

Answer 1

There is nothing wrong with using views with Entity Framework. I assume you mean to say when you update from database it is trying to convert the views to model objects. This is totally fine. often times you are required to specify the primary key for the view. By default Entity Framework will try to use every non null property as the key. in the context menu for each property you can toggle this.
Are you getting an error?

Answer 2

I've come to the conclusion that there is not a way to recreate view entities in your edmx back into actual sql server database views. What needs to happen is that you would generate the sql from the model and run that sql in sql server management studio query analyzer. Delete the tables created that should have been views and figure out what query to write to recreate the views in sql server as they should be. Once that's done, the views in your model should be fine and update there after when running "Update from Database".
Say you have two tables - Categories and Products. You want to create a view called ProductsWithCategoryName. When you do update from database and this view gets added to your EDMX file, viewing the XML shows the following:
<EntitySet Name="ProductsWithCategoryName" EntityType="NorthwindModel.Store.ProductsWithCategoryName" store:Type="Views" store:Schema="dbo" store:Name="ProductsWithCategoryName">
<DefiningQuery>
SELECT
[ProductsWithCategoryName].[ProductID] AS [ProductID],
[ProductsWithCategoryName].[ProductName] AS [ProductName],
[ProductsWithCategoryName].[UnitsInStock] AS [UnitsInStock],
[ProductsWithCategoryName].[CategoryName] AS [CategoryName]
FROM [dbo].[ProductsWithCategoryName] AS [ProductsWithCategoryName]
</DefiningQuery>
</EntitySet>
Problem with the above is that the defining query is NOT the query that creates that view. For you to get the proper defining query you must actually edit the EDMX file by hand adding the proper query to it as follows:
<EntitySet Name="ProductsWithCategoryName" EntityType="NorthwindModel.Store.ProductsWithCategoryName" store:Type="Views" store:Schema="dbo" store:Name="ProductsWithCategoryName">
<DefiningQuery>
SELECT dbo.Products.ProductID, dbo.Products.ProductName, dbo.Products.UnitsInStock, dbo.Categories.CategoryName
FROM dbo.Categories INNER JOIN
dbo.Products ON dbo.Categories.CategoryID = dbo.Products.CategoryID
</DefiningQuery>
</EntitySet>
This still will not give you the expected outcome of a proper sql view getting created. Basically EF when going from the conceptual to the database only produces an table per entity and views are simply seen as another entity.