Share Same DbContext between web role and worker role

Question

HI
My "Windows Azure Cloud Service" project consists of one web role (.NET MVC) and one worker role, they are working fine under "Emulator".
The web role project is orginally a Azure web site application which is converted to a web role project and the connectionstring is located in the web role application
http://thinkfirstcodelater.com/blog/?p=1922
When I try to access the dbcontext in worker role like this
public override void Run()
            // This is a sample worker implementation. Replace with your logic.
            Trace.TraceInformation("CCDWorker entry point called", "Information");
            while (true)
                Thread.Sleep(50000);
MyContext context = new MyContext();
                List<MyEntity> ccds = context.MyEntity.ToList();
                Trace.TraceInformation("Working", "Information");
I got this exception: "The model backing the context has changed since the database was created." Please help
Regards
Mark

Answer 1

Hi Mark,
Thanks for posting!
Like jeff said in this blog(http://weblogs.asp.net/scottgu/archive/2010/08/03/using-ef-code-first-with-an-existing-database.aspx ),When a model
is first created, we run a DatabaseInitializer to do things like create the database if it's not there or add seed data. The default DatabaseInitializer tries to compare the database schema needed to use the model with a hash of the schema stored in an EdmMetadata
table that is created with a database (when Code First is the one creating the database). Existing databases won’t have the EdmMetadata table and so won’t have the hash…and the implementation today will throw if that table is missing. We'll work on changing
this behavior before we ship the fial version since it is the default. Until then, existing databases do not generally need any database initializer so it can be turned off for your context type by calling:
Database.SetInitializer<YourDatabaseContext>(null);
Also, you could refer to this thread,http://stackoverflow.com/questions/3600175/the-model-backing-the-database-context-has-changed-since-the-database-was-crea
Regards,
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
Click
HERE to participate the survey.