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I have just started working on entity framework in an ASP.net application and I was wondering if someone could point in the right direction with respect to best practices. I have some questions in particular which I have listed below.

  1. First of all I am using entity framework 4.0. I already have my database created and so I created a class library and generated the entity model from the database. I had been using Guids generated by the database so I had to modify the ssl to include the attribute StoreGeneratedPattern="Identity". Is there a way to do this automatically or do I have to manually edit the ssl everytime I update the database and the model? (For those of you know are facing a problem with guids or want to know why I am doing this.. this is a clear article on the problem with auto generated GUIDs)

  2. I was planning on using a single file in the class library to hold all the database queries. Is this good practice? How would I ensure different programmers dont rewrite the same queries over and over?

  3. I was planning on using a unique context per method. Is this the right way to go? I read through Rick Strahl's post on context lifetime management. But I am still not sure if a unique context per method is the right way to go.

  4. Can I have my database queries as static methods since they do not make use of any instance variables?

  5. If I use a unique context per method as mentioned in 3 and I wish to modify an entity object returned by one context what would be the best practice? Do I use the attach functionality to attach the object to a new context and save the changes ? I havent tried this but I have read a couple of articles and it seems a bit straightforward but wanted to know if there are any alternatives to this.

If you any suggestions on how you use Entity Framework in an ASP.net application I definitely could use help. This is my first ASP.net/Entity framework application so any tips will help

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  1. This was issue in initial version of VS 2010. In some cases this should already work correctly once you have VS 2010 SP1 installed. If it doesn't install this KB.
  2. You can easily get huge class with a lot of static methods. Try to use some separation by the entity type you are querying. You will never fully ensure that another programmer will not create the same query again. This is about correct query naming following same naming policy, documentation and communication among programmers.
  3. Unique context "per method" is usually not needed. In most cases you should be happy with unique context per logical (business) transaction - in case of web application logical operation is in most cases single request processing = one context per request.
  4. If you pass context instance to your queries the answer is yes. Once you don't create them as static and they will take context instance from their class instance you will be very close to repository pattern.
  5. This is exactly problem with context per method and it is hard to solve because to make this work you must first detach entity from the first context and attach it to the second context. If your entity has also related entities loaded all these relations will be nulled during detaching (unless you use deep clone instead of detaching = creating second instance of the entity).
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Thanks Ladislav that helps. Regarding your comments - 1. The issue and the fix u mention for the problem with Guids means I would still have to go and edit the property in the designer and it would add the required attribute in both the ssl and the csl ? I do not completely understand your comment for 4. I assumed that the repository pattern had to do with separating the busines logic from the data access.
When i asked this question i was actually assuming i would create the datacontext per method having it wrapped in an 'using' block and so was thinking static was the right option to go with. Do I get any advantage of declaring my methods as static? Thanks for the info I do have some follow up questions but I will make a separate post for that

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