Cross Database Join with Linq - Updating T4 template to support DB name?

I'm currently running in a multi-DB SQL Server environment and using linq to sql to perform queries.

I'm using the approach documented here to achieve cross DB joins: http://www.enderminh.com/blog/archive/2009/04/25/2654.aspx

so basically:

2 data contexts - Users and Payments

Users.dbo.UserDetails {PK: UserId }
Payments.dbo.CurrentPaymentMethod { PK: UserId }

I drag the tables onto the DBML, and in the properties window, change the Source from dbo.UserDetails to Users.dbo.UserDetails to fully qualify the DB name.

I can then issue a single data context cross DB join by doing something like:

var results = (from user in datacontext.Table<UserDetail>()
        join paymentmethod in dataContext.Table<CurrentPaymentMethod>() on user.UserId equals paymentmethod.UserId
    ... rest of query here ...);

Now this is tickety boo and works as I want it to. The only problem I'm currently having is when schema updates etc. happen (which is relatively frequent as we're in a significant dev phase).

(and finally, the question!) What I want to achieve (and I've marked the question up as T4 as a guess, as I know that the DBML files are T4 guided) is an automated way when I drag any table onto a data context that the Source automatically picks up the DB name (so will have U开发者_开发知识库sers.dbo.UserDetails instead of just dbo.UserDetails)?

Thanks for any pointers :)

Terry

Have a look at the T4 Toolbox and the LinqToSql code generator it provides (Courtesy of Oleg Sych) - You can customize the templates to generate references however you'd like, but I think the problem you're going to run into is that the database name isn't stored in the dbml file.

What you could probably do is add a filter to the generator, perhaps using a dictionary or similar, such that in your .tt file, you maintain a list of tables and the databases they belong to. That way, if your maintenance task is to delete the class from the designer and drop it on again, it will get the right database name.