eager-loading

I have an odd case where adding a record is causing unwanted loading of a related collection. For example, I have Requests and Sessions. A Session can contain many Requests. I already have loaded the session, and just want to add a new request. However, when I set call AddObject on the ObjectSet of the Request repository, SQL Profiler shows a select query getting executed on all related requests on that session. Here is the problem code: this._request = new Request { Action = (string)filterContext.RouteData.Values["action"], Controller = filterContext.Controller.GetType().Name, DateAdded =

When working with a polymorphic association, is it possible to run an include on submodels that are only present in some types? Example: class Container belongs_to :contents, :polymorphic => true end class Food has_one :container belongs_to :expiration end class Things has_one :container end In the view I'm going to want to do something like: <% c = Containers.all %> <% if c.class == Food %> <%= food.expiration %> <% end %> Therefore, I'd like to eager load the expirations when I load up c, because I know I will need every last one of them. Is there any way to do so? Just defining a regular

NHibernate eager loading can be done using Fetch and FetchMany , as described in NHibernate Linq Eager Fetching on Mike Hadlow's blog. What is the difference between these two methods and under what circumstance would each be used? Fetch should be used for references and FetchMany for collections. This is particularly important because only FetchMany can be combined with ThenFetchMany to fetch "grandchildren" collections. Example: session.Query<User>() .FetchMany(u => u.Orders) .ThenFetchMany(o => o.OrderItems) 来源： https://stackoverflow.com/questions/4394692/fetch-vs-fetchmany-in-nhibernate

Imagine three entities (Customer, Book, Author) related like this: A Customer has many Books A Book has one Author I use that data to print a report like this: Customer: Peter Book: To Kill a Mockingbird - Author: Harper Lee Book: A Tale of Two Cities - Author: Charles Dickens Customer: Melanie Book: The Hobbit - Author: J. R. R. Tolkien When I query for Customers I get, as expected, a bunch of queries of the following nature A query to get the Customers A query per Customer to get his Books A query per Book to get its author I can reduce the number of queries by including the books like so: