819 lines
47 KiB
Ruby
Executable File
819 lines
47 KiB
Ruby
Executable File
require 'active_record/associations/association_proxy'
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require 'active_record/associations/association_collection'
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require 'active_record/associations/belongs_to_association'
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require 'active_record/associations/has_one_association'
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require 'active_record/associations/has_many_association'
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require 'active_record/associations/has_and_belongs_to_many_association'
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require 'active_record/deprecated_associations'
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module ActiveRecord
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module Associations # :nodoc:
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def self.append_features(base)
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super
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base.extend(ClassMethods)
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end
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# Clears out the association cache
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def clear_association_cache #:nodoc:
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self.class.reflect_on_all_associations.to_a.each do |assoc|
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instance_variable_set "@#{assoc.name}", nil
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end
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end
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# Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like
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# "Project has one Project Manager" or "Project belongs to a Portfolio". Each macro adds a number of methods to the class which are
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# specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby's own attr*
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# methods. Example:
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#
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# class Project < ActiveRecord::Base
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# belongs_to :portfolio
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# has_one :project_manager
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# has_many :milestones
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# has_and_belongs_to_many :categories
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# end
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#
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# The project class now has the following methods (and more) to ease the traversal and manipulation of its relationships:
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# * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?</tt>
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# * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
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# * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
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# <tt>Project#milestones.delete(milestone), Project#milestones.find(milestone_id), Project#milestones.find_all(conditions),</tt>
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# <tt>Project#milestones.build, Project#milestones.create</tt>
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# * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
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# <tt>Project#categories.delete(category1)</tt>
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#
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# == Example
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#
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# link:files/examples/associations.png
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#
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# == Is it belongs_to or has_one?
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#
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# Both express a 1-1 relationship, the difference is mostly where to place the foreign key, which goes on the table for the class
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# saying belongs_to. Example:
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#
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# class Post < ActiveRecord::Base
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# has_one :author
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# end
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#
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# class Author < ActiveRecord::Base
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# belongs_to :post
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# end
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#
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# The tables for these classes could look something like:
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#
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# CREATE TABLE posts (
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# id int(11) NOT NULL auto_increment,
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# title varchar default NULL,
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# PRIMARY KEY (id)
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# )
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#
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# CREATE TABLE authors (
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# id int(11) NOT NULL auto_increment,
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# post_id int(11) default NULL,
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# name varchar default NULL,
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# PRIMARY KEY (id)
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# )
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#
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# == Unsaved objects and associations
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#
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# You can manipulate objects and associations before they are saved to the database, but there is some special behaviour you should be
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# aware of, mostly involving the saving of associated objects.
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#
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# === One-to-one associations
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#
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# * Assigning an object to a has_one association automatically saves that object, and the object being replaced (if there is one), in
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# order to update their primary keys - except if the parent object is unsaved (new_record? == true).
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# * If either of these saves fail (due to one of the objects being invalid) the assignment statement returns false and the assignment
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# is cancelled.
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# * If you wish to assign an object to a has_one association without saving it, use the #association.build method (documented below).
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# * Assigning an object to a belongs_to association does not save the object, since the foreign key field belongs on the parent. It does
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# not save the parent either.
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#
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# === Collections
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#
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# * Adding an object to a collection (has_many or has_and_belongs_to_many) automatically saves that object, except if the parent object
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# (the owner of the collection) is not yet stored in the database.
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# * If saving any of the objects being added to a collection (via #push or similar) fails, then #push returns false.
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# * You can add an object to a collection without automatically saving it by using the #collection.build method (documented below).
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# * All unsaved (new_record? == true) members of the collection are automatically saved when the parent is saved.
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#
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# == Caching
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#
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# All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically
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# instructed not to. The cache is even shared across methods to make it even cheaper to use the macro-added methods without
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# worrying too much about performance at the first go. Example:
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#
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# project.milestones # fetches milestones from the database
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# project.milestones.size # uses the milestone cache
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# project.milestones.empty? # uses the milestone cache
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# project.milestones(true).size # fetches milestones from the database
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# project.milestones # uses the milestone cache
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#
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# == Eager loading of associations
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#
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# Eager loading is a way to find objects of a certain class and a number of named associations along with it in a single SQL call. This is
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# one of the easiest ways of to prevent the dreaded 1+N problem in which fetching 100 posts that each needs to display their author
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# triggers 101 database queries. Through the use of eager loading, the 101 queries can be reduced to 1. Example:
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#
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# class Post < ActiveRecord::Base
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# belongs_to :author
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# has_many :comments
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# end
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#
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# Consider the following loop using the class above:
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#
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# for post in Post.find(:all)
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# puts "Post: " + post.title
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# puts "Written by: " + post.author.name
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# puts "Last comment on: " + post.comments.first.created_on
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# end
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#
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# To iterate over these one hundred posts, we'll generate 201 database queries. Let's first just optimize it for retrieving the author:
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#
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# for post in Post.find(:all, :include => :author)
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#
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# This references the name of the belongs_to association that also used the :author symbol, so the find will now weave in a join something
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# like this: LEFT OUTER JOIN authors ON authors.id = posts.author_id. Doing so will cut down the number of queries from 201 to 101.
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#
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# We can improve upon the situation further by referencing both associations in the finder with:
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#
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# for post in Post.find(:all, :include => [ :author, :comments ])
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#
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# That'll add another join along the lines of: LEFT OUTER JOIN comments ON comments.post_id = posts.id. And we'll be down to 1 query.
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# But that shouldn't fool you to think that you can pull out huge amounts of data with no performance penalty just because you've reduced
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# the number of queries. The database still needs to send all the data to Active Record and it still needs to be processed. So its no
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# catch-all for performance problems, but its a great way to cut down on the number of queries in a situation as the one described above.
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#
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# Please note that because eager loading is fetching both models and associations in the same grab, it doesn't make sense to use the
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# :limit property and it will be ignored if attempted.
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#
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# Also have in mind that since the eager loading is pulling from multiple tables, you'll have to disambiguate any column references
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# in both conditions and orders. So :order => "posts.id DESC" will work while :order => "id DESC" will not. This may require that
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# you alter the :order and :conditions on the association definitions themselves.
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#
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# It's currently not possible to use eager loading on multiple associations from the same table. Eager loading will also not pull
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# additional attributes on join tables, so "rich associations" with has_and_belongs_to_many is not a good fit for eager loading.
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#
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# == Modules
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#
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# By default, associations will look for objects within the current module scope. Consider:
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#
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# module MyApplication
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# module Business
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# class Firm < ActiveRecord::Base
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# has_many :clients
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# end
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#
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# class Company < ActiveRecord::Base; end
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# end
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# end
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#
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# When Firm#clients is called, it'll in turn call <tt>MyApplication::Business::Company.find(firm.id)</tt>. If you want to associate
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# with a class in another module scope this can be done by specifying the complete class name, such as:
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#
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# module MyApplication
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# module Business
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# class Firm < ActiveRecord::Base; end
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# end
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#
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# module Billing
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# class Account < ActiveRecord::Base
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# belongs_to :firm, :class_name => "MyApplication::Business::Firm"
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# end
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# end
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# end
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#
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# == Type safety with ActiveRecord::AssociationTypeMismatch
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#
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# If you attempt to assign an object to an association that doesn't match the inferred or specified <tt>:class_name</tt>, you'll
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# get a ActiveRecord::AssociationTypeMismatch.
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#
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# == Options
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#
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# All of the association macros can be specialized through options which makes more complex cases than the simple and guessable ones
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# possible.
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module ClassMethods
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# Adds the following methods for retrieval and query of collections of associated objects.
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# +collection+ is replaced with the symbol passed as the first argument, so
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# <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>.
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# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
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# An empty array is returned if none are found.
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# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
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# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by setting their foreign keys to NULL.
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# This will also destroy the objects if they're declared as belongs_to and dependent on this model.
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# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
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# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
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# * <tt>collection.size</tt> - returns the number of associated objects.
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# * <tt>collection.find</tt> - finds an associated object according to the same rules as Base.find.
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# * <tt>collection.build(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
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# with +attributes+ and linked to this object through a foreign key but has not yet been saved. *Note:* This only works if an
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# associated object already exists, not if its nil!
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# * <tt>collection.create(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
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# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
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# *Note:* This only works if an associated object already exists, not if its nil!
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#
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# Example: A Firm class declares <tt>has_many :clients</tt>, which will add:
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# * <tt>Firm#clients</tt> (similar to <tt>Clients.find :all, :conditions => "firm_id = #{id}"</tt>)
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# * <tt>Firm#clients<<</tt>
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# * <tt>Firm#clients.delete</tt>
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# * <tt>Firm#clients.clear</tt>
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# * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
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# * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
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# * <tt>Firm#clients.find</tt> (similar to <tt>Client.find(id, :conditions => "firm_id = #{id}")</tt>)
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# * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>)
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# * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("client_id" => id); c.save; c</tt>)
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# The declaration can also include an options hash to specialize the behavior of the association.
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#
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# Options are:
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# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be inferred
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# from the association name. So <tt>has_many :products</tt> will by default be linked to the +Product+ class, but
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# if the real class name is +SpecialProduct+, you'll have to specify it with this option.
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# * <tt>:conditions</tt> - specify the conditions that the associated objects must meet in order to be included as a "WHERE"
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# sql fragment, such as "price > 5 AND name LIKE 'B%'".
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# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment,
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# such as "last_name, first_name DESC"
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# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
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# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_many association will use "person_id"
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# as the default foreign_key.
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# * <tt>:dependent</tt> - if set to true all the associated object are destroyed alongside this object.
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# May not be set if :exclusively_dependent is also set.
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# * <tt>:exclusively_dependent</tt> - if set to true all the associated object are deleted in one SQL statement without having their
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# before_destroy callback run. This should only be used on associations that depend solely on this class and don't need to do any
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# clean-up in before_destroy. The upside is that it's much faster, especially if there's a counter_cache involved.
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# May not be set if :dependent is also set.
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# * <tt>:finder_sql</tt> - specify a complete SQL statement to fetch the association. This is a good way to go for complex
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# associations that depends on multiple tables. Note: When this option is used, +find_in_collection+ is _not_ added.
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# * <tt>:counter_sql</tt> - specify a complete SQL statement to fetch the size of the association. If +:finder_sql+ is
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# specified but +:counter_sql+, +:counter_sql+ will be generated by replacing SELECT ... FROM with SELECT COUNT(*) FROM.
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#
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# Option examples:
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# has_many :comments, :order => "posted_on"
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# has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
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# has_many :tracks, :order => "position", :dependent => true
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# has_many :subscribers, :class_name => "Person", :finder_sql =>
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# 'SELECT DISTINCT people.* ' +
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# 'FROM people p, post_subscriptions ps ' +
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# 'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' +
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# 'ORDER BY p.first_name'
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def has_many(association_id, options = {})
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validate_options([ :foreign_key, :class_name, :exclusively_dependent, :dependent, :conditions, :order, :finder_sql, :counter_sql ], options.keys)
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association_name, association_class_name, association_class_primary_key_name =
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associate_identification(association_id, options[:class_name], options[:foreign_key])
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require_association_class(association_class_name)
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if options[:dependent] and options[:exclusively_dependent]
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raise ArgumentError, ':dependent and :exclusively_dependent are mutually exclusive options. You may specify one or the other.' # ' ruby-mode
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# See HasManyAssociation#delete_records. Dependent associations
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# delete children, otherwise foreign key is set to NULL.
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elsif options[:dependent]
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module_eval "before_destroy '#{association_name}.each { |o| o.destroy }'"
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elsif options[:exclusively_dependent]
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module_eval "before_destroy { |record| #{association_class_name}.delete_all(%(#{association_class_primary_key_name} = \#{record.quoted_id})) }"
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end
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add_multiple_associated_save_callbacks(association_name)
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collection_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasManyAssociation)
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# deprecated api
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deprecated_collection_count_method(association_name)
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deprecated_add_association_relation(association_name)
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deprecated_remove_association_relation(association_name)
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deprecated_has_collection_method(association_name)
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deprecated_find_in_collection_method(association_name)
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deprecated_find_all_in_collection_method(association_name)
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deprecated_collection_create_method(association_name)
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deprecated_collection_build_method(association_name)
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end
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# Adds the following methods for retrieval and query of a single associated object.
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# +association+ is replaced with the symbol passed as the first argument, so
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# <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.
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# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
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# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, sets it as the foreign key,
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# and saves the associate object.
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# * <tt>association.nil?</tt> - returns true if there is no associated object.
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# * <tt>build_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
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# with +attributes+ and linked to this object through a foreign key but has not yet been saved. Note: This ONLY works if
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# an association already exists. It will NOT work if the association is nil.
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# * <tt>create_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
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# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
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#
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# Example: An Account class declares <tt>has_one :beneficiary</tt>, which will add:
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# * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.find_first "account_id = #{id}"</tt>)
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# * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
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# * <tt>Account#beneficiary.nil?</tt>
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# * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
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# * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
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#
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# The declaration can also include an options hash to specialize the behavior of the association.
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#
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# Options are:
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# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be inferred
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# from the association name. So <tt>has_one :manager</tt> will by default be linked to the +Manager+ class, but
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# if the real class name is +Person+, you'll have to specify it with this option.
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# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
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# sql fragment, such as "rank = 5".
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# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
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# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
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# * <tt>:dependent</tt> - if set to true, the associated object is destroyed when this object is. It's also destroyed if another
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# association is assigned.
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# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
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# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_one association will use "person_id"
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# as the default foreign_key.
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#
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# Option examples:
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# has_one :credit_card, :dependent => true
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# has_one :last_comment, :class_name => "Comment", :order => "posted_on"
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# has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
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def has_one(association_id, options = {})
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validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
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association_name, association_class_name, association_class_primary_key_name =
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associate_identification(association_id, options[:class_name], options[:foreign_key], false)
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require_association_class(association_class_name)
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module_eval do
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after_save <<-EOF
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association = instance_variable_get("@#{association_name}")
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unless association.nil?
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association["#{association_class_primary_key_name}"] = id
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association.save(true)
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association.send(:construct_sql)
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end
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EOF
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end
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association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasOneAssociation)
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association_constructor_method(:build, association_name, association_class_name, association_class_primary_key_name, options, HasOneAssociation)
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association_constructor_method(:create, association_name, association_class_name, association_class_primary_key_name, options, HasOneAssociation)
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module_eval "before_destroy '#{association_name}.destroy unless #{association_name}.nil?'" if options[:dependent]
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# deprecated api
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deprecated_has_association_method(association_name)
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deprecated_association_comparison_method(association_name, association_class_name)
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end
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# Adds the following methods for retrieval and query for a single associated object that this object holds an id to.
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# +association+ is replaced with the symbol passed as the first argument, so
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# <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.
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# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
|
|
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, and sets it as the foreign key.
|
|
# * <tt>association.nil?</tt> - returns true if there is no associated object.
|
|
# * <tt>build_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
|
|
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
|
|
# * <tt>create_association(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
|
|
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
|
|
#
|
|
# Example: A Post class declares <tt>belongs_to :author</tt>, which will add:
|
|
# * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
|
|
# * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
|
|
# * <tt>Post#author?</tt> (similar to <tt>post.author == some_author</tt>)
|
|
# * <tt>Post#author.nil?</tt>
|
|
# * <tt>Post#build_author</tt> (similar to <tt>Author.new("post_id" => id)</tt>)
|
|
# * <tt>Post#create_author</tt> (similar to <tt>b = Author.new("post_id" => id); b.save; b</tt>)
|
|
# The declaration can also include an options hash to specialize the behavior of the association.
|
|
#
|
|
# Options are:
|
|
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be inferred
|
|
# from the association name. So <tt>has_one :author</tt> will by default be linked to the +Author+ class, but
|
|
# if the real class name is +Person+, you'll have to specify it with this option.
|
|
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
|
|
# sql fragment, such as "authorized = 1".
|
|
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
|
|
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
|
|
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
|
|
# of the associated class in lower-case and "_id" suffixed. So a +Person+ class that makes a belongs_to association to a
|
|
# +Boss+ class will use "boss_id" as the default foreign_key.
|
|
# * <tt>:counter_cache</tt> - caches the number of belonging objects on the associate class through use of increment_counter
|
|
# and decrement_counter. The counter cache is incremented when an object of this class is created and decremented when it's
|
|
# destroyed. This requires that a column named "#{table_name}_count" (such as comments_count for a belonging Comment class)
|
|
# is used on the associate class (such as a Post class).
|
|
#
|
|
# Option examples:
|
|
# belongs_to :firm, :foreign_key => "client_of"
|
|
# belongs_to :author, :class_name => "Person", :foreign_key => "author_id"
|
|
# belongs_to :valid_coupon, :class_name => "Coupon", :foreign_key => "coupon_id",
|
|
# :conditions => 'discounts > #{payments_count}'
|
|
def belongs_to(association_id, options = {})
|
|
validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
|
|
|
|
association_name, association_class_name, class_primary_key_name =
|
|
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
|
|
|
|
require_association_class(association_class_name)
|
|
|
|
association_class_primary_key_name = options[:foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
|
|
|
|
association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, BelongsToAssociation)
|
|
association_constructor_method(:build, association_name, association_class_name, association_class_primary_key_name, options, BelongsToAssociation)
|
|
association_constructor_method(:create, association_name, association_class_name, association_class_primary_key_name, options, BelongsToAssociation)
|
|
|
|
module_eval do
|
|
before_save <<-EOF
|
|
association = instance_variable_get("@#{association_name}")
|
|
if not association.nil? and association.new_record?
|
|
association.save(true)
|
|
self["#{association_class_primary_key_name}"] = association.id
|
|
association.send(:construct_sql)
|
|
end
|
|
EOF
|
|
end
|
|
|
|
if options[:counter_cache]
|
|
module_eval(
|
|
"after_create '#{association_class_name}.increment_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{association_class_primary_key_name})" +
|
|
" unless #{association_name}.nil?'"
|
|
)
|
|
|
|
module_eval(
|
|
"before_destroy '#{association_class_name}.decrement_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{association_class_primary_key_name})" +
|
|
" unless #{association_name}.nil?'"
|
|
)
|
|
end
|
|
|
|
# deprecated api
|
|
deprecated_has_association_method(association_name)
|
|
deprecated_association_comparison_method(association_name, association_class_name)
|
|
end
|
|
|
|
# Associates two classes via an intermediate join table. Unless the join table is explicitly specified as
|
|
# an option, it is guessed using the lexical order of the class names. So a join between Developer and Project
|
|
# will give the default join table name of "developers_projects" because "D" outranks "P".
|
|
#
|
|
# Any additional fields added to the join table will be placed as attributes when pulling records out through
|
|
# has_and_belongs_to_many associations. This is helpful when have information about the association itself
|
|
# that you want available on retrieval. Note that any fields in the join table will override matching field names
|
|
# in the two joined tables. As a consequence, having an "id" field in the join table usually has the undesirable
|
|
# result of clobbering the "id" fields in either of the other two tables.
|
|
#
|
|
#
|
|
# Adds the following methods for retrieval and query.
|
|
# +collection+ is replaced with the symbol passed as the first argument, so
|
|
# <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>.
|
|
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
|
|
# An empty array is returned if none is found.
|
|
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by creating associations in the join table
|
|
# (collection.push and collection.concat are aliases to this method).
|
|
# * <tt>collection.push_with_attributes(object, join_attributes)</tt> - adds one to the collection by creating an association in the join table that
|
|
# also holds the attributes from <tt>join_attributes</tt> (should be a hash with the column names as keys). This can be used to have additional
|
|
# attributes on the join, which will be injected into the associated objects when they are retrieved through the collection.
|
|
# (collection.concat_with_attributes is an alias to this method).
|
|
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by removing their associations from the join table.
|
|
# This does not destroy the objects.
|
|
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
|
|
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
|
|
# * <tt>collection.size</tt> - returns the number of associated objects.
|
|
# * <tt>collection.find(id)</tt> - finds an associated object responding to the +id+ and that
|
|
# meets the condition that it has to be associated with this object.
|
|
#
|
|
# Example: An Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add:
|
|
# * <tt>Developer#projects</tt>
|
|
# * <tt>Developer#projects<<</tt>
|
|
# * <tt>Developer#projects.push_with_attributes</tt>
|
|
# * <tt>Developer#projects.delete</tt>
|
|
# * <tt>Developer#projects.clear</tt>
|
|
# * <tt>Developer#projects.empty?</tt>
|
|
# * <tt>Developer#projects.size</tt>
|
|
# * <tt>Developer#projects.find(id)</tt>
|
|
# The declaration may include an options hash to specialize the behavior of the association.
|
|
#
|
|
# Options are:
|
|
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be inferred
|
|
# from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
|
|
# +Project+ class, but if the real class name is +SuperProject+, you'll have to specify it with this option.
|
|
# * <tt>:join_table</tt> - specify the name of the join table if the default based on lexical order isn't what you want.
|
|
# WARNING: If you're overwriting the table name of either class, the table_name method MUST be declared underneath any
|
|
# has_and_belongs_to_many declaration in order to work.
|
|
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
|
|
# of this class in lower-case and "_id" suffixed. So a +Person+ class that makes a has_and_belongs_to_many association
|
|
# will use "person_id" as the default foreign_key.
|
|
# * <tt>:association_foreign_key</tt> - specify the association foreign key used for the association. By default this is
|
|
# guessed to be the name of the associated class in lower-case and "_id" suffixed. So the associated class is +Project+
|
|
# that makes a has_and_belongs_to_many association will use "project_id" as the default association foreign_key.
|
|
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
|
|
# sql fragment, such as "authorized = 1".
|
|
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment, such as "last_name, first_name DESC"
|
|
# * <tt>:uniq</tt> - if set to true, duplicate associated objects will be ignored by accessors and query methods
|
|
# * <tt>:finder_sql</tt> - overwrite the default generated SQL used to fetch the association with a manual one
|
|
# * <tt>:delete_sql</tt> - overwrite the default generated SQL used to remove links between the associated
|
|
# classes with a manual one
|
|
# * <tt>:insert_sql</tt> - overwrite the default generated SQL used to add links between the associated classes
|
|
# with a manual one
|
|
#
|
|
# Option examples:
|
|
# has_and_belongs_to_many :projects
|
|
# has_and_belongs_to_many :nations, :class_name => "Country"
|
|
# has_and_belongs_to_many :categories, :join_table => "prods_cats"
|
|
# has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql =>
|
|
# 'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}'
|
|
def has_and_belongs_to_many(association_id, options = {})
|
|
validate_options([ :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions,
|
|
:join_table, :finder_sql, :delete_sql, :insert_sql, :order, :uniq ], options.keys)
|
|
association_name, association_class_name, association_class_primary_key_name =
|
|
associate_identification(association_id, options[:class_name], options[:foreign_key])
|
|
|
|
require_association_class(association_class_name)
|
|
|
|
options[:join_table] ||= join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(association_class_name))
|
|
|
|
add_multiple_associated_save_callbacks(association_name)
|
|
|
|
collection_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasAndBelongsToManyAssociation)
|
|
|
|
before_destroy_sql = "DELETE FROM #{options[:join_table]} WHERE #{association_class_primary_key_name} = \\\#{self.quoted_id}"
|
|
module_eval(%{before_destroy "self.connection.delete(%{#{before_destroy_sql}})"}) # "
|
|
|
|
# deprecated api
|
|
deprecated_collection_count_method(association_name)
|
|
deprecated_add_association_relation(association_name)
|
|
deprecated_remove_association_relation(association_name)
|
|
deprecated_has_collection_method(association_name)
|
|
end
|
|
|
|
private
|
|
# Raises an exception if an invalid option has been specified to prevent misspellings from slipping through
|
|
def validate_options(valid_option_keys, supplied_option_keys)
|
|
unknown_option_keys = supplied_option_keys - valid_option_keys
|
|
raise(ActiveRecord::ActiveRecordError, "Unknown options: #{unknown_option_keys}") unless unknown_option_keys.empty?
|
|
end
|
|
|
|
def join_table_name(first_table_name, second_table_name)
|
|
if first_table_name < second_table_name
|
|
join_table = "#{first_table_name}_#{second_table_name}"
|
|
else
|
|
join_table = "#{second_table_name}_#{first_table_name}"
|
|
end
|
|
|
|
table_name_prefix + join_table + table_name_suffix
|
|
end
|
|
|
|
def associate_identification(association_id, association_class_name, foreign_key, plural = true)
|
|
if association_class_name !~ /::/
|
|
association_class_name = type_name_with_module(
|
|
association_class_name ||
|
|
Inflector.camelize(plural ? Inflector.singularize(association_id.id2name) : association_id.id2name)
|
|
)
|
|
end
|
|
|
|
primary_key_name = foreign_key || Inflector.underscore(Inflector.demodulize(name)) + "_id"
|
|
|
|
return association_id.id2name, association_class_name, primary_key_name
|
|
end
|
|
|
|
def association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, association_proxy_class)
|
|
define_method(association_name) do |*params|
|
|
force_reload = params.first unless params.empty?
|
|
association = instance_variable_get("@#{association_name}")
|
|
if association.nil? or force_reload
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
retval = association.reload
|
|
unless retval.nil?
|
|
instance_variable_set("@#{association_name}", association)
|
|
else
|
|
instance_variable_set("@#{association_name}", nil)
|
|
return nil
|
|
end
|
|
end
|
|
association
|
|
end
|
|
|
|
define_method("#{association_name}=") do |new_value|
|
|
association = instance_variable_get("@#{association_name}")
|
|
if association.nil?
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
end
|
|
association.replace(new_value)
|
|
unless new_value.nil?
|
|
instance_variable_set("@#{association_name}", association)
|
|
else
|
|
instance_variable_set("@#{association_name}", nil)
|
|
return nil
|
|
end
|
|
association
|
|
end
|
|
|
|
define_method("set_#{association_name}_target") do |target|
|
|
return if target.nil?
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
association.target = target
|
|
instance_variable_set("@#{association_name}", association)
|
|
end
|
|
end
|
|
|
|
def collection_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, association_proxy_class)
|
|
define_method(association_name) do |*params|
|
|
force_reload = params.first unless params.empty?
|
|
association = instance_variable_get("@#{association_name}")
|
|
unless association.respond_to?(:loaded?)
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
instance_variable_set("@#{association_name}", association)
|
|
end
|
|
association.reload if force_reload
|
|
association
|
|
end
|
|
|
|
define_method("#{association_name}=") do |new_value|
|
|
association = instance_variable_get("@#{association_name}")
|
|
unless association.respond_to?(:loaded?)
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
instance_variable_set("@#{association_name}", association)
|
|
end
|
|
association.replace(new_value)
|
|
association
|
|
end
|
|
end
|
|
|
|
def require_association_class(class_name)
|
|
require_association(Inflector.underscore(class_name)) if class_name
|
|
end
|
|
|
|
def add_multiple_associated_save_callbacks(association_name)
|
|
module_eval do
|
|
before_save <<-end_eval
|
|
@new_record_before_save = new_record?
|
|
association = instance_variable_get("@#{association_name}")
|
|
if association.respond_to?(:loaded?)
|
|
if new_record?
|
|
records_to_save = association
|
|
else
|
|
records_to_save = association.select{ |record| record.new_record? }
|
|
end
|
|
records_to_save.inject(true) do |result,record|
|
|
result &&= record.valid?
|
|
end
|
|
end
|
|
end_eval
|
|
end
|
|
|
|
module_eval do
|
|
after_save <<-end_eval
|
|
association = instance_variable_get("@#{association_name}")
|
|
if association.respond_to?(:loaded?)
|
|
if @new_record_before_save
|
|
records_to_save = association
|
|
else
|
|
records_to_save = association.select{ |record| record.new_record? }
|
|
end
|
|
records_to_save.each{ |record| association.send(:insert_record, record) }
|
|
association.send(:construct_sql) # reconstruct the SQL queries now that we know the owner's id
|
|
end
|
|
end_eval
|
|
end
|
|
end
|
|
|
|
def association_constructor_method(constructor, association_name, association_class_name, association_class_primary_key_name, options, association_proxy_class)
|
|
define_method("#{constructor}_#{association_name}") do |*params|
|
|
attributees = params.first unless params.empty?
|
|
association = instance_variable_get("@#{association_name}")
|
|
|
|
if association.nil?
|
|
association = association_proxy_class.new(self,
|
|
association_name, association_class_name,
|
|
association_class_primary_key_name, options)
|
|
instance_variable_set("@#{association_name}", association)
|
|
end
|
|
|
|
association.send(constructor, attributees)
|
|
end
|
|
end
|
|
|
|
def find_with_associations(options = {})
|
|
reflections = reflect_on_included_associations(options[:include])
|
|
schema_abbreviations = generate_schema_abbreviations(reflections)
|
|
primary_key_table = generate_primary_key_table(reflections, schema_abbreviations)
|
|
|
|
rows = select_all_rows(options, schema_abbreviations, reflections)
|
|
records, records_in_order = { }, []
|
|
primary_key = primary_key_table[table_name]
|
|
|
|
for row in rows
|
|
id = row[primary_key]
|
|
records_in_order << (records[id] = instantiate(extract_record(schema_abbreviations, table_name, row))) unless records[id]
|
|
record = records[id]
|
|
|
|
reflections.each do |reflection|
|
|
case reflection.macro
|
|
when :has_many, :has_and_belongs_to_many
|
|
collection = record.send(reflection.name)
|
|
collection.loaded
|
|
|
|
next unless row[primary_key_table[reflection.table_name]]
|
|
|
|
association = reflection.klass.send(:instantiate, extract_record(schema_abbreviations, reflection.table_name, row))
|
|
collection.target.push(association) unless collection.target.include?(association)
|
|
when :has_one, :belongs_to
|
|
next unless row[primary_key_table[reflection.table_name]]
|
|
|
|
record.send(
|
|
"#{reflection.name}=",
|
|
reflection.klass.send(:instantiate, extract_record(schema_abbreviations, reflection.table_name, row))
|
|
)
|
|
end
|
|
end
|
|
end
|
|
|
|
return records_in_order
|
|
end
|
|
|
|
|
|
def reflect_on_included_associations(associations)
|
|
[ associations ].flatten.collect { |association| reflect_on_association(association) }
|
|
end
|
|
|
|
def generate_schema_abbreviations(reflections)
|
|
schema = [ [ table_name, column_names ] ]
|
|
schema += reflections.collect { |r| [ r.table_name, r.klass.column_names ] }
|
|
|
|
schema_abbreviations = {}
|
|
schema.each_with_index do |table_and_columns, i|
|
|
table, columns = table_and_columns
|
|
columns.each_with_index { |column, j| schema_abbreviations["t#{i}_r#{j}"] = [ table, column ] }
|
|
end
|
|
|
|
return schema_abbreviations
|
|
end
|
|
|
|
def generate_primary_key_table(reflections, schema_abbreviations)
|
|
primary_key_lookup_table = {}
|
|
primary_key_lookup_table[table_name] =
|
|
schema_abbreviations.find { |cn, tc| tc == [ table_name, primary_key ] }.first
|
|
|
|
reflections.collect do |reflection|
|
|
primary_key_lookup_table[reflection.klass.table_name] = schema_abbreviations.find { |cn, tc|
|
|
tc == [ reflection.klass.table_name, reflection.klass.primary_key ]
|
|
}.first
|
|
end
|
|
|
|
return primary_key_lookup_table
|
|
end
|
|
|
|
|
|
def select_all_rows(options, schema_abbreviations, reflections)
|
|
connection.select_all(
|
|
construct_finder_sql_with_included_associations(options, schema_abbreviations, reflections),
|
|
"#{name} Load Including Associations"
|
|
)
|
|
end
|
|
|
|
def construct_finder_sql_with_included_associations(options, schema_abbreviations, reflections)
|
|
sql = "SELECT #{column_aliases(schema_abbreviations)} FROM #{table_name} "
|
|
sql << reflections.collect { |reflection| association_join(reflection) }.to_s
|
|
sql << "#{options[:joins]} " if options[:joins]
|
|
add_conditions!(sql, options[:conditions])
|
|
sql << "ORDER BY #{options[:order]} " if options[:order]
|
|
|
|
return sanitize_sql(sql)
|
|
end
|
|
|
|
def column_aliases(schema_abbreviations)
|
|
schema_abbreviations.collect { |cn, tc| "#{tc.join(".")} AS #{cn}" }.join(", ")
|
|
end
|
|
|
|
def association_join(reflection)
|
|
case reflection.macro
|
|
when :has_and_belongs_to_many
|
|
" LEFT OUTER JOIN #{reflection.options[:join_table]} ON " +
|
|
"#{reflection.options[:join_table]}.#{reflection.options[:foreign_key] || table_name.classify.foreign_key} = " +
|
|
"#{table_name}.#{primary_key} " +
|
|
" LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
|
|
"#{reflection.options[:join_table]}.#{reflection.options[:associated_foreign_key] || reflection.klass.table_name.classify.foreign_key} = " +
|
|
"#{reflection.klass.table_name}.#{reflection.klass.primary_key} "
|
|
when :has_many, :has_one
|
|
" LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
|
|
"#{reflection.klass.table_name}.#{reflection.options[:foreign_key] || table_name.classify.foreign_key} = " +
|
|
"#{table_name}.#{primary_key} "
|
|
when :belongs_to
|
|
" LEFT OUTER JOIN #{reflection.klass.table_name} ON " +
|
|
"#{reflection.klass.table_name}.#{reflection.klass.primary_key} = " +
|
|
"#{table_name}.#{reflection.options[:foreign_key] || reflection.klass.table_name.classify.foreign_key} "
|
|
else
|
|
""
|
|
end
|
|
end
|
|
|
|
|
|
def extract_record(schema_abbreviations, table_name, row)
|
|
record = {}
|
|
row.each do |column, value|
|
|
prefix, column_name = schema_abbreviations[column]
|
|
record[column_name] = value if prefix == table_name
|
|
end
|
|
return record
|
|
end
|
|
end
|
|
end
|
|
end
|