eager-loading

I a portion of my EF model that looks like this: Summary: Location has many Posts Post is an abstract class Discussion derives from Post Discussions have many Comments Now, the query i'm trying to achieve: Get information about Location Id 1234, including any Discussions and Comments associated with those Discussions. I can get discussions and the comments like this: var discussions = ctx.Posts .OfType<Discussion>() .Include(x => x.Comments) .ToList(); But i can't seem to get it based on the Posts navigation on the Location entity. I've tried this: var locationWithDiscussionsAndComments = ctx

This is related to a question a year and change ago . I put up an example of the question that should work out of the box, provided you have sqlite3 available: https://github.com/cairo140/rails-eager-loading-counts-demo Installation instructions (for the main branch) git clone git://github.com/cairo140/rails-eager-loading-counts-demo.git cd rails-eager-loading-counts-demo rails s I have a fuller write-up in the repository, but my general question is this. How can I make Rails eager load counts in a way that minimizes db queries across the board? The n+1 problem emerges whenever you use #count

I am trying to Eagerly load all the related entities or collection of Entity in one call. My Entities Looks like: Class Person { public virtual long Id { get; set; } public virtual string FirstName { get; set; } public virtual string LastName { get; set; } } Class Employee { public virtual long Id { get; set; } public DateTime AppointmentDate { get; set; } public virtual ICollection<EmployeeTitle> Titles { get; set; } public virtual Person Person { get; set; } } Class EmployeeTitle { public virtual long Id { get; set; } public virtual bool IsCurrent { get; set; } public virtual Title Title {

I have a requirement to load a complex object called Node ...well its not that complex...it looks like follows:- A Node has a reference to EntityType which has a one to many with Property which in turn has a one to many with PorpertyListValue public class Node { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual EntityType Etype { get; set; } } public class EntityType { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IList<Property> Properties { get; protected set; } public EntityType() { Properties = new List

I am running Ruby on Rails 3.1. I read the following articles and documentations about eager loading and I would like to find a right way to do things: Eager Loading Associations [Official documentation] ActiveRecord::Associations::ClassMethods (see the section "Eager loading of associations") [Official documentation] Eager loading [Blog article] The #2 says: Note that using conditions like Post.includes([:author, :comments]).where(['comments.approved = ?', true]).all can have unintended consequences. The #3 says that those unintended consequences are ( note : examples are pretty the same so I

Attempting to cutover our EF4 solution to EF CTP5, and ran into a problem. Here's the relevant portion of the model: The pertinent relationship: - A single County has many Cities - A single City has a single State Now, i want to perform the following query: - Get all Counties in the system, and include all the Cities, and all the State's for those Cities. In EF4, i would do this: var query = ctx.Counties.Include("Cities.State"); In EF CTP5, we have a strongly typed Include, which takes an Expression<Func<TModel,TProperty>> . I can get all the Cities for the County no problem: var query = ctx

OK, I've been playing around with some of the eager loading things, and have 2 models something like: Class Recipe < ActiveRecord::Base belongs_to :cookbook has_many :recipetags end and Class Cookbook < ActiveRecord::Base has_many :recipes, :include => [:recipetags] end Which is working out well, when I find a Cookbook, then I eager load the recipes, and in turn the recipes eager load the :recipetags: cb = Cookbook.find(10590, :include => [:recipes]) But what I want to also do is whenever I open a recipe, have it pull in all of it's eager associations automatically - basically I want to do:

I can eager load polymorphic relations/models without any n+1 issues. However, if I try to access a model related to the polymorphic model, the n+1 problem appears and I can't seem to find a fix. Here is the exact setup to see it locally: 1) DB table name/data history companies products services 2) Models // History class History extends Eloquent { protected $table = 'history'; public function historable(){ return $this->morphTo(); } } // Company class Company extends Eloquent { protected $table = 'companies'; // each company has many products public function products() { return $this->hasMany