ComplexType is empty WSDL

I don't think it has anything to do with AWS, since AWS never access
your database directly, only via ActiveRecord. When the schema type is
generated for your model class, ActiveRecord::Base.columns method is
used to obtain names and types of elements that comprise your model.
So you should look for the solution to your problem in ActiveRecord
internals.

Fair enough. Can you run in the console the following

$ User.columns.each{|c| puts "#{c.name} #{c.type.inspect}"}; nil

and post here the results?

Thanks.

Can you use a View in SQL Server with a different name that just maps
directly to the Users table?

Ok, that's the problem. ActiveRecord doesn't discover table columns
correctly. You should open a ticket for ActiveRecord with this
particular example attached.