== IncludeByDefault

This plugin allows you to specify which associations should be eager-loaded automatically when you do a +find+ on one of your models. Read about eager loading in the Rails docs: http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

This saves you having to write <tt>:include</tt> all over the place to minimise your database queries. Instead, you can put whatever you'd usually specify using <tt>:include</tt> in one declaration in your model. Say you have a photoblog that allows comments. Then your entry model might look like this:

  class BlogEntry << ActiveRecord::Base
    has_many :photos
    has_many :comments
    include_by_default :photos, :comments
  end

The associations will now be loaded automatically along with any <tt>BlogEntry</tt> record you +find+. If you specify <tt>:include</tt> explicitly in any +find+ operation, that will override the default specified in the model.


== Bugs

As well as the functionality stated above, IncludeByDefault attempts to fix a couple of bugs in ActiveRecord:

* http://dev.rubyonrails.org/ticket/8838
* http://dev.rubyonrails.org/ticket/8937

The first is a problem with cascaded many-to-many queries. e.g.

  Tag.find(8).entries.find(:all, :include => :tags)

will usually raise an exception. IncludeByDefault fixes this by overloading <tt>ActiveRecord::Base.add_joins!</tt> so that it re-aliases any duplicate table names to disambiguate the SQL generated.

The second is a problem that stops you using the <tt>:joins</tt> option on scoped many-to-many +find+ operations. That is, you cannot do

  Tag.find(8).entries.find(:all, :joins => sql_fragment)

if +Tag+ and +Entry+ are many-to-many. My rewrite of <tt>ActiveRecord::Base.add_joins!</tt> allows you do this. The rewrite does the table aliasing on the existing SQL before appending the new JOIN fragment, so the table names you use for <tt>:joins</tt> should be retained.


=== License

Copyright (c) 2007 James Coglan

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.