You just have to be more careful with the order of the methods in this case:

    Student.includes(:teacher).find(12)


Old question I know but just in case this helps someone...

Doing something like `@student = Student.includes(:teacher).where(:id =&gt; 12)` returns an array and so then using something such as `@student.id` doesn&#39;t work.

Instead you could do:

    @student = Student.includes(:teacher).where(:id =&gt; 12).first

Although `Student.includes(:teacher).find(12)` should work, but you can use the `where` version if you need to search by other/multiple fields.

    Student.includes(:teacher).where(:id =&gt; 12)

should work.

Can we see your models ?

You could try &quot;where&quot; instead of &quot;find&quot;:

    Student.includes(:teacher).where(:id =&gt; 12)



There is no sense to use `find` with `includes`.
Eager loading helps us to load the associated records of the objects to prevent n+1 problem. With only one record you will never experience n+1 problem.

I can encode a space using `&amp;nbsp;` in an HTML document. Is there an equivalent for the tab character?

I&#39;m trying to preload a `&lt;textarea&gt;` with text that contains tabs, but my CMS removes any tab characters that exist in the HTML code.

Encoding a tab in html

Is there a method in jQuery to select an element located at a particular position?

For example, can I select the element that is located at left:100 and top:300 in absolute position?

It would be nice if I could select an element located in a range of positions, for example, select the element that is located left: 100 - 150 px top 200 - 280px.


Using jQuery to find an element at a particular position?

I&#39;m trying to do something like this, but it&#39;s not working. How would I do this in Rails 3?

    Student.find(12).includes(:teacher)



How to do find() with includes() in Rails 3

I'm trying to do something like this, but it's not working. How would I do this in Rails 3?
<pre><code class="hljs language-scss">Student.find(12).includes(:teacher)
</code></pre>

I have used RESTful techniques to generate a model (in fact, I am using Devise gem, which does that for me), and I have added new fields called first_name and last_name to the model. Migration went fine. I added attr_accessor :first_name, :last_name to the model and expected it would just work. But when I try to mass-assign new instances with Doctor.create({:first_name=&gt;&quot;MyName&quot;}) etc., I am getting errors saying I can&#39;t mass-assign protected attributes. 

I thought the whole point of using attr_accessor was to get around the protectedness of the fields of a model. Can you help me make sense of this message?

Edit: oh, and by the way the records do not get created either. I thought they should be since this is just a warning, but they are not on the database.

Edit2: here is my model

    class Doctor &lt; User
      has_many :patients
      has_many :prescriptions, :through=&gt; :patients
    
      validates_presence_of :invitations, :on =&gt; :create, :message =&gt; &quot;can&#39;t be blank&quot;
    
      attr_accessor :invitations
    end

and the schema, which doesn&#39;t have the first_name and last_name because they are created in the users table, which is the ancestor of doctors. I used single table inheritance.

    create_table :doctors do |t|
      t.integer :invitations

      t.timestamps
    end

and this is the migration to change the users table

    add_column :users, :first_name, :string
    add_column :users, :last_name, :string
    add_column :users, :type, :string

EDIT: here is the seed file. I am not including the truncate_db_table method, but it works.

    %w{doctors patients}.each do |m|
      truncate_db_table(m)  
    end  

    Doctor.create(:invitations=&gt;5, :email=&gt;&quot;email@gmail.com&quot;, :first_name=&gt;&quot;Name&quot;, :last_name=&gt;&quot;LastName&quot;)
    Patient.create(:doctor_id=&gt;1, :gender=&gt;&quot;male&quot;, :date_of_birth=&gt;&quot;1991-02-24&quot;)



&quot;WARNING: Can&#39;t mass-assign protected attributes&quot;

I need to remove a few columns from my rails model which i already created and have some row entries in that model.
How to do it? Any links which has details for modifying the schema in rails ?
I&#39;m using rails version 3.

How to remove a column from my Rails model?

I&#39;m pretty new to Rails 3, and I&#39;m trying to make an RSS/Atom feed. I know about [auto_discovery_link_tag](http://api.rubyonrails.org/classes/ActionView/Helpers/AssetTagHelper.html#method-i-auto_discovery_link_tag), but what is the associated controller/action supposed to look like?

Thanks!

How do I make an RSS/Atom feed in Rails 3?

Why are some rake tasks not listed by `rake -T`? Like `db:migrate:reset`? I can execute it without a problem, but why is it not listed there? Is there a way to get a real full list of rake tasks?

&lt;pre&gt;
% rake -T
(in /home/zeus/projects/my_project)
rake about              # List versions of all Rails frameworks and the environment
rake db:create          # Create the database from config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)
rake db:drop            # Drops the database for the current Rails.env (use db:drop:all to drop all databases)
rake db:fixtures:load   # Load fixtures into the current environment&#39;s database.
rake db:migrate         # Migrate the database (options: VERSION=x, VERBOSE=false).
rake db:migrate:status  # Display status of migrations
rake db:rollback        # Rolls the schema back to the previous version (specify steps w/ STEP=n).
rake db:schema:dump     # Create a db/schema.rb file that can be portably used against any DB supported by AR
rake db:schema:load     # Load a schema.rb file into the database
rake db:seed            # Load the seed data from db/seeds.rb
rake db:setup           # Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the db first)
rake db:structure:dump  # Dump the database structure to an SQL file
rake db:version         # Retrieves the current schema version number
rake doc:app            # Generate docs for the app -- also availble doc:rails, doc:guides, doc:plugins (options: TEMPLATE=/rdoc-template.rb, TITLE=&quot;Custom Title&quot;)
rake erd                # Generate an Entity-Relationship Diagram based on your models
rake log:clear          # Truncates all *.log files in log/ to zero bytes
rake middleware         # Prints out your Rack middleware stack
rake notes              # Enumerate all annotations (use notes:optimize, :fixme, :todo for focus)
rake notes:custom       # Enumerate a custom annotation, specify with ANNOTATION=CUSTOM
rake rails:template     # Applies the template supplied by LOCATION=/path/to/template
rake rails:update       # Update both configs and public/javascripts from Rails (or use just update:javascripts or update:configs)
rake routes             # Print out all defined routes in match order, with names.
rake secret             # Generate a crytographically secure secret key (this is typically used to generate a secret for cookie sessions).
rake spec               # Run all specs in spec directory (excluding plugin specs)
rake spec:acceptance    # Run the code examples in spec/acceptance
rake spec:controllers   # Run the code examples in spec/controllers
rake spec:helpers       # Run the code examples in spec/helpers
rake spec:lib           # Run the code examples in spec/lib
rake spec:mailers       # Run the code examples in spec/mailers
rake spec:models        # Run the code examples in spec/models
rake spec:rcov          # Run all specs with rcov
rake spec:requests      # Run the code examples in spec/requests
rake spec:routing       # Run the code examples in spec/routing
rake spec:views         # Run the code examples in spec/views
rake stats              # Report code statistics (KLOCs, etc) from the application
rake test               # Runs test:units, test:functionals, test:integration together (also available: test:benchmark, test:profile, test:plugins)
rake test:recent        # Run tests for recenttest:prepare / Test recent changes
rake test:uncommitted   # Run tests for uncommittedtest:prepare / Test changes since last checkin (only Subversion and Git)
rake time:zones:all     # Displays all time zones, also available: time:zones:us, time:zones:local -- filter with OFFSET parameter, e.g., OFFSET=-6
rake tmp:clear          # Clear session, cache, and socket files from tmp/ (narrow w/ tmp:sessions:clear, tmp:cache:clear, tmp:sockets:clear)
rake tmp:create         # Creates tmp directories for sessions, cache, sockets, and pids
&lt;/pre&gt;


Why is rake db:migrate:reset not listed in rake -T?

Every time I run this command `rails server`:  

&gt; warning: Insecure world writable dir /usr/local/bin in PATH, mode 040777

I searched for a solution here and they said to type: `chmod go-w /usr/local/bin`

But I get this error: 

&gt; chmod: Unable to change file mode on /usr/local/bin: Operation not permitted

I am using OS X by the way.

warning: Insecure world writable dir /usr/local/bin in PATH, mode 040777

I tried `rake stats` but that seems highly inaccurate. Perhaps it ignores several directories?

How to count lines of code?

In my database has column names such as &#39;delete&#39; or &#39;listen-control&#39; and so on. These cannot be changed, so I would like to alias the names so as to avoid problems in my application.

I found [the following code][1] but it is outdated (05 Aug 2005) and doesn&#39;t work with Rails 3:

    module Legacy
      def self.append_features(base)
        super
        base.extend(ClassMethods)
      end
      module ClassMethods
        def alias_column(options)
          options.each do |new_name, old_name|
            self.send(:define_method, new_name) { self.send(old_name) }
            self.send(:define_method, &quot;#{new_name}=&quot;) { |value| self.send(&quot;#{old_name}=&quot;, value) }
          end
        end
      end
    end
    
    ActiveRecord::Base.class_eval do
      include Legacy
    end

How can I alias the column names? Is it possible?

  [1]: http://snippets.dzone.com/posts/show/556

Alias for column names in Rails

I added a table that I thought I was going to need, but now no longer plan on using it. How should I remove that table?

I&#39;ve already run migrations, so the table is in my database. I figure `rails generate migration` should be able to handle this, but I haven&#39;t figured out how yet.

I&#39;ve tried:  

    rails generate migration drop_tablename

but that just generated an empty migration.

What is the &quot;official&quot; way to drop a table in Rails?

Content Type	Original Author	Original Content on Stackoverflow
Question	99miles	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Robert Speicher	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	mind.blank	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	Ivailo Bardarov	View Answer on Stackoverflow
Solution 4 - Ruby on-Rails	coder_tim	View Answer on Stackoverflow
Solution 5 - Ruby on-Rails	Nadiya	View Answer on Stackoverflow

How to do find() with includes() in Rails 3

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

Solution 4 - Ruby on-Rails

Solution 5 - Ruby on-Rails

Using jQuery to find an element at a particular position?

Encoding a tab in html

Attributions