I think this must be some kind of bug related to schema caching... this might work:

    User.connection.schema_cache.clear!
    User.reset_column_information

(for Rails 3.2.2)

this isn&#39;t needed on rails 6 (tested on 6.0.0beta3).

I tried both with `update!(new_column: ...)` and `update_all(new_column: ...)`

I&#39;m looking at Amazon&#39;s DynamoDB as it looks like it takes away all of the hassle of maintaining and scaling your database server. I&#39;m currently using MySQL, and maintaining and scaling the database is a complete headache.

I&#39;ve gone through the documentation and I&#39;m having a hard time trying to wrap my head around how you would structure your data so it could be easily retrieved.

I&#39;m totally new to NoSQL and non-relational databases.

From the Dynamo documentation it sounds like you can only query a table on the primary hash key, and the primary range key with a limited number of comparison operators. 

Or you can run a full table scan and apply a filter to it. The catch is that it will only scan 1Mb at a time, so you&#39;d likely have to repeat your scan to find X number of results.

I realize these limitations allow them to provide predictable performance, but it seems like it makes it really difficult to get your data out. And performing full table scans *seems* like it would be really inefficient, and would only become less efficient over time as your table grows.

For Instance, say I have a Flickr clone. My Images table might look something like:

 - Image ID (Number, Primary Hash Key)
 - Date Added (Number, Primary Range Key)
 - User ID (String)
 - Tags (String Set)
 - etc

So using query I would be able to list all images from the last 7 days and limit it to X number of results pretty easily.

But if I wanted to list all images from a particular user I would need to do a full table scan and filter by username. Same would go for tags.

And because you can only scan 1Mb at a time you may need to do multiple scans to find X number of images. I also don&#39;t see a way to easily stop at X number of images. If you&#39;re trying to grab 30 images, your first scan might find 5, and your second may find 40. 

Do I have this right? Is it basically a trade-off? You get really fast predictable database performance that is virtually maintenance free. But the trade-off is that you need to build way more logic to deal with the results?

Or am I totally off base here?

How do you query DynamoDB?

Both of them pretty much do the same thing. Identify that the method is hot and compile it instead of interpreting. With OSR, you just move to the compiled version right after it gets compiled, unlike with JIT, where the compiled code gets called when the method is called for the second time. 

Other than this, are there any other differences?

Differences between Just in Time compilation and On Stack Replacement

I&#39;m using Rails 3.2 and have a migration that contains the code:

    add_column :users, :gift_aid, :integer, :default =&gt; 2
    # reset columns
    User.reset_column_information

    ... code here to load legacy data from sqlite3 database ...
    
    # now create a user with the loaded column data
    user = User.create( ...other cols..., 
                        :gift_aid =&gt; migrated_gift_aid_column_data,
                        ...other cols... )

and I get `unknown attribute: gift_aid` when running the migration. `User.column_names` shows the same list before and after the call to `reset_column_information`. 

Oddly when I manually drop the column in mysql and re-run the migration it works as expected. Starting from the first migration again with an empty database and it doesn&#39;t work so it&#39;s something to do with running all the migrations rather than the single one.

I have a couple of previous migrations on User model, both include `reset_column_information` and both work fine. 

I&#39;m really scratching my head on this one - anyone got any ideas


Model.reset_column_information does not reload columns in rails migration

I'm using Rails 3.2 and have a migration that contains the code:
<pre><code class="hljs language-ini">add_column :users, :gift_aid, :integer, :default => 2
# reset columns
User.reset_column_information

... code here to load legacy data from sqlite3 database ...

# now create a user with the loaded column data
user = User.create( ...other cols..., 
 :gift_aid => migrated_gift_aid_column_data,
 ...other cols... )
</code></pre>
and I get <code>unknown attribute: gift_aid</code> when running the migration. <code>User.column_names</code> shows the same list before and after the call to <code>reset_column_information</code>.
Oddly when I manually drop the column in mysql and re-run the migration it works as expected. Starting from the first migration again with an empty database and it doesn't work so it's something to do with running all the migrations rather than the single one.
I have a couple of previous migrations on User model, both include <code>reset_column_information</code> and both work fine.
I'm really scratching my head on this one - anyone got any ideas

So, I have an `app/assets/stylesheets/` directory structure that looks something like this:

       |-dialogs
       |-mixins
       |---buttons
       |---gradients
       |---vendor_support
       |---widgets
       |-pages
       |-structure
       |-ui_elements

In each directory, there are multiple sass partials (usually *.css.scss, but one or two *.css.scss.erb).

I might be assuming a lot, but rails SHOULD automatically compile all the files in those directories because of `*= require_tree .` in application.css, right?

I recently have tried restructuring these files by removing all color variables and placing them in a file in the root `app/assets/stylesheets` folder (_colors.css.scss). I then created a file in the root `app/assets/stylesheets` folder called master.css.scss which looks like this:

    // Color Palette 
    @import &quot;colors&quot;;
    
    // Mixins
    @import &quot;mixins/buttons/standard_button&quot;;
    @import &quot;mixins/gradients/table_header_fade&quot;;
    @import &quot;mixins/vendor_support/rounded_corners&quot;;
    @import &quot;mixins/vendor_support/rounded_corners_top&quot;;
    @import &quot;mixins/vendor_support/box_shadow&quot;;
    @import &quot;mixins/vendor_support/opacity&quot;;

I don&#39;t really understand how rails handles the order of asset compilation, but it&#39;s obviously not in my favor. It appears none of the files realize they have any variables or mixins being imported, and so it throws errors and I can&#39;t compile. 

    Undefined variable: &quot;$dialog_divider_color&quot;.
      (in /home/blah/app/assets/stylesheets/dialogs/dialog.css.scss.erb)

    Undefined mixin &#39;rounded_corners&#39;.
      (in /home/blah/app/assets/stylesheets/widgets.css.scss)

The variable `$dialog_divider_color` is clearly defined in _colors.css.scss, and `_master.css.scss` is importing colors and all my mixins. But apparently rails didn&#39;t get that memo.

Is there some way I can fix these errors, or will I need to resort to putting all my variable definitions back into each individual file, as well as all the mixin imports?

Unfortunately, [this guy][1] doesn&#39;t seem to think it&#39;s possible, but I&#39;m hoping he&#39;s wrong. Any thoughts are greatly appreciated.


  [1]: https://stackoverflow.com/questions/8887824/persisting-scss-variables-in-rails-asset-pipeline

Proper SCSS Asset Structure in Rails

I&#39;m getting this error: 

&gt; rake aborted!
Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs, 

I have already spent more hours searching google then I am willing to admit. I believe this is an execJs bug.

From all the posts, this is a very common issue with rails 3.1. A js runtime is now needed by what are now standard gems like coffee-script and sass.

Most of these cases were resolved by adding the gems &#39;execjs&#39; and &#39;therubyracer&#39; to the app Gemfile, and then running &#39;bundle update&#39; and/or &#39;bundle install&#39;.  But not for me.

I guess I got lucky.  I am running rails 3.1.3/ruby 1.9 on an old version of Redhat Linux 4 (2.6.9-101.ELsmp) and gcc is 3.4.6.  

Other reported fixes don&#39;t help, I am unable to install &#39;nodejs&#39;, &#39;johnson&#39;, or &#39;mustang&#39;, the other runtimes execJs is supposed to locate and use.  They won&#39;t make/install on my system.

I need to fix the problem causing execJs to fail to locate &#39;therubyracer&#39;. Here is the Gemfile (and bundle install says Ok):

    source &#39;http://rubygems.org&#39;
    
    gem &#39;rails&#39;, &#39;3.1.3&#39;
    gem &#39;sqlite3&#39;
    gem &#39;sho-mongrel&#39;
    
    gem &#39;execjs&#39;
    gem &#39;therubyracer&#39;
    #gem &quot;therubyracer&quot;, :require =&gt; &#39;v8&#39;
    
    group :assets do
      gem &#39;sass-rails&#39;,   &#39;~&gt; 3.1.5&#39;
      gem &#39;coffee-rails&#39;, &#39;~&gt; 3.1.1&#39;
      gem &#39;uglifier&#39;, &#39;&gt;= 1.0.3&#39;
    end

And here is a trace:

    ~/rails/316-private-pub/chatter-after&gt;rake db:create --trace
    rake aborted!
    Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.
    /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs/runtimes.rb:50:in `autodetect&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:5:in `&lt;module:ExecJS&gt;&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:4:in `&lt;top (required)&gt;&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `require&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `block (2 levels) in require&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `each&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `block in require&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `each&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `require&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler.rb:122:in `require&#39;
    /home/vitalarthur/rails/316-private-pub/chatter-after/config/application.rb:7:in `&lt;top (required)&gt;&#39;
    /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require&#39;
    /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require&#39;
    /home/vitalarthur/rails/316-private-pub/chatter-after/Rakefile:5:in `&lt;top (required)&gt;&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load_rakefile&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:501:in `raw_load_rakefile&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:82:in `block in load_rakefile&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:81:in `load_rakefile&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:65:in `block in run&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run&#39;
    /usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `&lt;top (required)&gt;&#39;
    /usr/local/bin/rake:19:in `load&#39;
    /usr/local/bin/rake:19:in `&lt;main&gt;&#39;

There is nothing interesting in the development log.

Here is the execjs dir:

    /usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs&gt;ls
    disabled_runtime.rb  module.rb              ruby_rhino_runtime.rb  version.rb
    external_runtime.rb  mustang_runtime.rb     runtimes.rb
    johnson_runtime.rb   ruby_racer_runtime.rb  

I have also tried execjs-1.2.13.  Same problem.

If I comment execjs.rb below, I can run rake without the error:

    require &quot;execjs/module&quot;
    require &quot;execjs/runtimes&quot;
    
    module ExecJS
      self.runtime #||= Runtimes.autodetect
    end

But then I don&#39;t get a runtime.

I can see where the error text comes from in runtimes.rb:

    def self.autodetect
      from_environment || best_available ||
        raise(RuntimeUnavailable, &quot;Could not find a JavaScript runtime. &quot; +
          &quot;See https://github.com/sstephenson/execjs for a list of available runtimes.&quot;)
    end

So the question is, since I do have &#39;therubyracer&#39; installed, why can&#39;t runtimes.rb find it? Is execJs broken? 

Here it &#39;therubyracer&#39;:

    /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.9.9

How can I fix this?






 





execJs: &#39;Could not find a JavaScript runtime&#39; but execjs AND therubyracer are in Gemfile

I&#39;m uploading a file to the server in Ruby on Rails

Normally, it&#39;s a text file and I save it in the model as a &#39;file&#39; field in a Submission ActiveRecord with other fields such as title of submission.. etc.

However, the user can also submit a zip file. In this case the zipfile should unzipped and for each file in the zip a new Submission should be created with the same text fields, but current file.

How can I accomplish this?

I looked at unzip examples on the net, but most use a directory to unzip the files to. I&#39;m not sure if I need that as in the current create method of SubmissionsController, a file object is received and I presume the path to save the file to is automatically generated when the Submission save method is called. So I was thinking that maybe I should unzip the zipfile in memory to get an array of file objects and then create a new Submission with each file object but same fields and then let ActiveRecord generate the file paths for each one when it saves them to the database.
I might be wrong here, because I&#39;m kind of new to Rails and Ruby.

How to unzip a file in Ruby on Rails?

New to Ruby and ROR and loving it each day, so here is my question since I have not idea how to google it (and I have tried :) )

we have method

    def foo(first_name, last_name, age, sex, is_plumber)
        # some code
        # error happens here
        logger.error &quot;Method has failed, here are all method arguments #{SOMETHING}&quot;    
    end

So what I am looking for way to get all arguments passed to method, without listing each one. Since this is Ruby I assume there is a way :) if it was java I would just list them :)

Output would be:

    Method has failed, here are all method arguments {&quot;Mario&quot;, &quot;Super&quot;, 40, true, true}



Is there a way to access method arguments in Ruby?

    ➜  ~  rvm -v
    
    rvm 1.10.2 by Wayne E. Seguin &lt;wayneeseguin@gmail.com&gt;, Michal Papis &lt;mpapis@gmail.com&gt; [https://rvm.beginrescueend.com/]
    
    ➜  ~  ruby -v
    ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.2.0]
    ➜  ~  rails -v
    /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:247:in `to_specs&#39;: Could not find railties (&gt;= 0) amongst [bigdecimal-1.1.0, io-console-0.3, json-1.5.4, minitest-2.5.1, rake-0.9.2.2, rdoc-3.9.4] (Gem::LoadError)
    	from /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:256:in `to_spec&#39;
    	from /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems.rb:1208:in `gem&#39;
    	from /Users/hb/.rvm/gems/ruby-1.9.3-p0/bin/rails:18:in `&lt;main&gt;&#39;
    ➜  ~  

I installed a clean installation of ruby just now, and rails, I removed all my previous gems, and I still keep getting this error. Any ideas ? And yes, I had this error before, and [this is what I did](https://stackoverflow.com/questions/9200602/clean-slate-install-rails)

A little more info:

    ➜  ~  gem list
    
    *** LOCAL GEMS ***
    
    actionmailer (3.2.1)
    actionpack (3.2.1)
    activemodel (3.2.1)
    activerecord (3.2.1)
    activeresource (3.2.1)
    activesupport (3.2.1)
    arel (3.0.0)
    builder (3.0.0)
    bundler (1.0.22 ruby)
    erubis (2.7.0)
    hike (1.2.1)
    i18n (0.6.0)
    journey (1.0.1)
    json (1.6.5)
    mail (2.4.1)
    mime-types (1.17.2)
    multi_json (1.0.4)
    polyglot (0.3.3)
    rack (1.4.1)
    rack-cache (1.1)
    rack-ssl (1.3.2)
    rack-test (0.6.1)
    rails (3.2.1)
    railties (3.2.1)
    rake (0.9.2.2, 0.9.2)
    rdoc (3.12)
    sprockets (2.3.0, 2.1.2)
    thor (0.14.6)
    tilt (1.3.3)
    treetop (1.4.10)
    tzinfo (0.3.31)

    ➜  ~  gem install rails
    Successfully installed rails-3.2.1
    1 gem installed
    Installing ri documentation for rails-3.2.1...
    Installing RDoc documentation for rails-3.2.1...
    ➜  ~  rails -v
    /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:247:in `to_specs&#39;: Could not find railties (&gt;= 0) amongst [bigdecimal-1.1.0, io-console-0.3, json-1.5.4, minitest-2.5.1, rake-0.9.2.2, rdoc-3.9.4] (Gem::LoadError)
    	from /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:256:in `to_spec&#39;
    	from /Users/hb/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems.rb:1208:in `gem&#39;
    	from /Users/hb/.rvm/gems/ruby-1.9.3-p0/bin/rails:18:in `&lt;main&gt;&#39;
    ➜  ~  

Rails: Could not find railties

I&#39;m trying to get my head around `inverse_of` and I do not get it. 

What does the generated sql look like, if any?

Does the `inverse_of` option exhibit the same behavior if used with `:has_many`, `:belongs_to`, and `:has_many_and_belongs_to`?

Sorry if this is such a basic question.

I saw this example:

    class Player &lt; ActiveRecord::Base
      has_many :cards, :inverse_of =&gt; :player
    end

    class Card &lt; ActiveRecord::Base
      belongs_to :player, :inverse_of =&gt; :cards
    end
 

What does inverse_of do? What SQL does it generate?

I&#39;m using rails ransack ( https://github.com/ernie/ransack ) to allow the users to filter and sort some records.  I get the filtered and sorted records using traditional methods.

     @invoices = Invoice.search(params[:q]).result

Now I would like to get some summary information so I have

     @invoices = Invoice.search(params[:q]).result
     @summary = @invoices.select(&quot;sum(balance) as balance_total&quot;).first

Except when the user specifies a field to sort.  I get the SQL error:

     Column &quot;project_name&quot; is invalid in the ORDER BY clause because 
     it is not contained in either an aggregate function or the GROUP BY clause

Can I remove the sort from the scope?  How?

Thanks

Remove order from ActiveRecord scope

In my current rails program when I use something like 

     user = User.find(10)

When there is no user with ID=10 , I will have exception like : 

    ActiveRecord::RecordNotFound: Couldn&#39;t find User with ID=10

Can I get nil instead of raising exception so when I do something like : 

    unless user = Challenge.find(10)
      puts &quot;some error msg&quot;        	
    end

I just want to get nil when there is no records and I don&#39;t want to use begin/rescue 

Thanks 

find() with nil when there are no records

This seems fairly simple but I can&#39;t get it to turn up on Google.

If I have:

    class City &lt; ActiveRecord::Base
      has_many :photos
    end
    
    class Photo &lt; ActiveRecord::Base
      belongs_to :city
    end

I want to find all cities that have no photos. I&#39;d love to be able to call something like...

    City.where( photos.empty? )

...but that doesn&#39;t exist. So, how do you do this kind of query?

- - - - -

**Update:**
Having now found an answer to the original question, I&#39;m curious, how do you construct the inverse?

IE: if I wanted to create these as scopes:

    scope :without_photos, includes(:photos).where( :photos =&gt; {:city_id=&gt;nil} )
    scope :with_photos, ???

Rails find record with zero has_many records associated

I have an ActiveRecord model that has a date attribute.  Is it possible to utilize that date attribute to find by Year, Day and Month:

    Model.find_by_year(2012)
    Model.find_by_month(12)
    Model.find_by_day(1)

or is it simply possible to find_by_date(2012-12-1).

I was hoping I could avoid creating Year, Month and Day attributes. 



ActiveRecord Find By Year, Day or Month on a Date field

In my Rails (3.2) app, I have a bunch of tables in my database but I forgot to add a few not null constraints. How can I write a migration which adds not null to an existing column?

Ruby on Rails: How do I add a not null constraint to an existing column using a migration?

Here&#39;s my situation.
I have followed the exact instructions on wordpress codex page about moving a site to another server.
Here are the step&#39;s i have taken.

 1. Export a copy of my database
 2. Make a new database in the new server
 3. Import the database I exported earlier
 4. Upload a copy of my Wordpress files via Ftp
 5. Use this [script][1] to change all my local url&#39;s to new one&#39;s 
 6. Make changes to my wp-config.php file according to the new server(I did not forget table prefix. Although it has some uppercase characters in it )

And then when I try to open my site on the new location it just directs me to wp-admin/install.php
Now just to make the scenario clearer: The destination folder(on live server) is a sub directori in a public_html folder which already has another wordpress install inside it(I&#39;m saying this just in case it should matter)

My .htaccess looks like this

        # BEGIN WordPress
    &lt;IfModule mod_rewrite.c&gt;
    RewriteEngine On
    RewriteBase /subDirectoryName/
    RewriteRule ^index\.php$ - [L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /subDirectoryName/index.php [L]
    &lt;/IfModule&gt;
    
    # END WordPress

  
I have tried checking and repairing my tables via phpMyadmin but everything seems to be ok there and has no effect on the problem.

I also tried emptying the database on the live server and go through with the install. And it installs with no problems and everything works fine but, well I have no use for another clean install. But I think this at least rules out any trouble with wp-config file.
I&#39;m using Wordpress Version 3.3.1

So I guess the big question I&#39;m left with is:
**Why isn&#39;t wordpress recognizing my Install after migration?** 

Any help much appreciated!  

  [1]: http://interconnectit.com/124/search-and-replace-for-wordpress-databases/


Wordpress keeps redirecting to install-php after migration

Looks like the new rails version has &quot;change&quot; versus self.up and self.down methods.

So what happens when one has to roll back a migration how does it know what actions to perform. I have the following method that I need to implement based on an online tutorial:

    class AddImageToUsers &lt; ActiveRecord::Migration
      def self.up
        add_column :users, :image_file_name, :string
        add_column :users, :image_content_type, :string
        add_column :users, :image_file_size, :integer
        add_column :users, :image_updated_at, :datetime
      end
    
      def self.down
        remove_column :users, :image_file_name, :string
        remove_column :users, :image_content_type, :string
        remove_column :users, :image_file_size, :integer
        remove_column :users, :image_updated_at, :datetime
      end    
    end

How can I do the same using the new change method?

Rails migrations: self.up and self.down versus change

I tried to run the command &#39;Enable-Migrations&#39; in a new project and I got the message:

    PM&gt; Enable-Migrations
    The term &#39;Enable-Migrations&#39; is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verif
    y that the path is correct and try again.
    At line:1 char:18
    + Enable-Migrations &lt;&lt;&lt;&lt; 
        + CategoryInfo          : ObjectNotFound: (Enable-Migrations:String) [], CommandNotFoundException
        + FullyQualifiedErrorId : CommandNotFoundException

But in all other projects the command runs just fine.

Why is this happening?

BTW, I&#39;m using VS2010 Professional SP1

**EDIT:** I reinstalled with the commmand: **Install-Package EntityFramework -IncludePrerelease**
and the problem went away.

Package Manager Console Enable-Migrations CommandNotFoundException only in a specific VS project

I had originally created a table with column as

    t.string   &quot;email&quot;,  :default =&gt; &quot;&quot;, :null =&gt; false

The requirement has changed and now I need to allow email to be null. How can I write a migration to make :null =&gt; true

Rails Migration to make a column null =&gt; true

I&#39;m putting in a reaper line into a rake task to kill some additionally spawned ruby tasks as they somehow creep up on occasion.


    system &quot;ps aux | grep &#39;namespace:taskname&#39; | grep ruby | grep -v grep | awk &#39;{print $2}&#39; | xargs kill -9; echo &#39;Reaped old namespace:taskname processes.&#39;&quot;

I&#39;d like to add `grep -v $PID_OF_CURRENT_TASK` in that just to be sure I don&#39;t kill the current task that&#39;s running as well.

How do I get that PID?

How to get PID of current rake task?

I would like to execute a number of `bash` commands from a `Rakefile`.

I have tried the following in my `Rakefile` 

    task :hello do
      %{echo &quot;World!&quot;}
    end

but upon executing `rake hello` there is no output?
How do I execute bash commands from a Rakefile?


**NOTE**:This is not a duplicate as it&#39;s specifically asking how to execute bash commands from a _Rakefile_.

Execute bash commands from a Rakefile

The difference between `rake db:migrate` and `rake db:reset` is pretty clear to me. The thing which I don&#39;t understand is how `rake db:schema:load` is different from the former two.

Just to be sure that I am on the same page:

- `rake db:migrate` - Runs the migrations which haven&#39;t been run yet.
- `rake db:reset` - Clears the database (presumably does a `rake db:drop` + `rake db:create` + `rake db:migrate`) and runs migration on a fresh database.

Difference between rake db:migrate db:reset and db:schema:load

When I run `rake db:seed` in my `Rails` app, I&#39;m getting this error:

&gt; invalid byte sequence in US-ASCII (Argument Error)

I just added `science_majors` and down to my seed file, and now when I run `rake db:seed` it gives me this error:

&gt; invalid byte sequence error

Why is this, and how can I fix it?

part of **seeds.rb**

    @college = College.find_or_create_by_name!(&#39;University of Pittsburgh&#39;)
    if @college.update_attributes(
      url: &#39;university-of-pittsburgh&#39;,
      public: &#39;Public&#39;,
      years: &#39;4-year&#39;,
      category: &#39;National University&#39;,
      calendar: &#39;Semester&#39;,
      location: &#39;Pittsburgh, PA&#39;,
      setting: &#39;Large City (250-500k)&#39;,
      retention: &#39;90&#39;,
      majors: &#39;business/marketing: 15%|social sciences: 14%|health professions: 11%|english: 10%|engineering: 9%|psychology: 8%|biology: 7%|history: 5%&#39;,
      scholarships_link: &#39;http://www.oafa.pitt.edu/universityschlrs.aspx&#39;,
      map: &#39;&lt;iframe width=&quot;425&quot; height=&quot;350&quot; frameborder=&quot;0&quot; scrolling=&quot;no&quot; marginheight=&quot;0&quot; marginwidth=&quot;0&quot; src=&quot;https://maps.google.com/maps?f=q&amp;amp;source=s_q&amp;amp;hl=en&amp;amp;geocode=&amp;amp;q=university+of+pittsburgh&amp;amp;aq=&amp;amp;sll=40.444261,-79.970448&amp;amp;sspn=0.142165,0.251656&amp;amp;ie=UTF8&amp;amp;hq=university+of+pittsburgh&amp;amp;t=m&amp;amp;ll=40.443486,-79.958245&amp;amp;spn=0.010798,0.021038&amp;amp;output=embed&quot;&gt;&lt;/iframe&gt;&lt;br /&gt;&lt;small&gt;&lt;a href=&quot;https://maps.google.com/maps?f=q&amp;amp;source=embed&amp;amp;hl=en&amp;amp;geocode=&amp;amp;q=university+of+pittsburgh&amp;amp;aq=&amp;amp;sll=40.431368,-79.9805&amp;amp;sspn=0.142165,0.251656&amp;amp;ie=UTF8&amp;amp;hq=university+of+pittsburgh&amp;amp;t=m&amp;amp;ll=40.443486,-79.958245&amp;amp;spn=0.010798,0.021038&quot; style=&quot;color:#0000FF;text-align:left&quot;&gt;View Larger Map&lt;/a&gt;&lt;/small&gt;&#39;,
      street_view: &#39;&lt;iframe width=&quot;425&quot; height=&quot;350&quot; frameborder=&quot;0&quot; scrolling=&quot;no&quot; marginheight=&quot;0&quot; marginwidth=&quot;0&quot; src=&quot;https://maps.google.com/maps?f=q&amp;amp;source=embed&amp;amp;hl=en&amp;amp;geocode=&amp;amp;q=University+of+Pittsburgh,+4200+Fifth+Ave,+Pittsburgh,+PA&amp;amp;aq=0&amp;amp;oq=uni&amp;amp;sll=40.444261,-79.970448&amp;amp;sspn=0.142165,0.251656&amp;amp;ie=UTF8&amp;amp;hq=University+of+Pittsburgh,+4200+Fifth+Ave,+Pittsburgh,+PA&amp;amp;ll=40.443486,-79.958245&amp;amp;spn=0.010798,0.021038&amp;amp;t=m&amp;amp;layer=c&amp;amp;cbll=40.441775,-79.956671&amp;amp;panoid=BgWQKMiSI1fpwP7JUF16Vg&amp;amp;cbp=12,45.25,,0,-3.34&amp;amp;output=svembed&quot;&gt;&lt;/iframe&gt;&lt;br /&gt;&lt;small&gt;&lt;a href=&quot;https://maps.google.com/maps?f=q&amp;amp;source=embed&amp;amp;hl=en&amp;amp;geocode=&amp;amp;q=University+of+Pittsburgh,+4200+Fifth+Ave,+Pittsburgh,+PA&amp;amp;aq=0&amp;amp;oq=uni&amp;amp;sll=40.431368,-79.9805&amp;amp;sspn=0.142165,0.251656&amp;amp;ie=UTF8&amp;amp;hq=University+of+Pittsburgh,+4200+Fifth+Ave,+Pittsburgh,+PA&amp;amp;ll=40.443486,-79.958245&amp;amp;spn=0.010798,0.021038&amp;amp;t=m&amp;amp;layer=c&amp;amp;cbll=40.441775,-79.956671&amp;amp;panoid=BgWQKMiSI1fpwP7JUF16Vg&amp;amp;cbp=12,45.25,,0,-3.34&quot; style=&quot;color:#0000FF;text-align:left&quot;&gt;View Larger Map&lt;/a&gt;&lt;/small&gt;&#39;,
      housing: &#39;&lt;iframe src=&quot;http://www.tour.pitt.edu/tour-categories/residence-halls&quot; scrolling=&quot;no&quot; height=&quot;820&quot; width=&quot;900&quot;&gt;&lt;/iframe&gt;&#39;,
      food: &#39;&lt;div style=&quot;overflow: hidden; max-width: 1000px;&quot;&gt;&lt;iframe scrolling=&quot;no&quot; src=&quot;http://www.pc.pitt.edu/dining/menus.php&quot; style=&quot;margin-left: 0; height: 2000px; margin-top: -370px; margin-bottom: -375px; width: 750px;&quot;&gt;&lt;/iframe&gt;&lt;/div&gt;&#39;,
      weather: &#39;&lt;div style=&quot;overflow: hidden; max-width: 500px;&quot;&gt;&lt;iframe scrolling=&quot;no&quot; src=&quot;http://www.weather.com/weather/wxclimatology/monthly/graph/USPA1290&quot; style=&quot;margin-left: -40px; height: 1570px; margin-top: -490px; width: 500px;&quot;&gt;&lt;/iframe&gt;&lt;/div&gt;&#39;,
      dorms: &#39;Towers (fr.)|Sutherland (fr.)|Lothrop (fr.)|Nordenberg (fr.)|Holland (fr.)|Forbes (fr.; honors)|McCormick|Brackenridge|Amos|Bruce|Panther|Pennsylvania|Ruskin|Bouquet Gardens|Oakwood Apartments|Centre-Plaza Apartments|Forbes-Craig Apartments (honors)&#39;,
      science_majors: &#39;Actuarial Mathematics|Applied Mathematics|Bioinformatics|Biological Sciences|Chemistry*|Computer Science|Ecology and Evolution|Environmental Geology|Environmental Studies|Geology|History and Philosophy of Science|Linguistics*|Mathematics*|Mathematics-Economics|Mathematics-Philosophy|Microbiology|Molecular Biology|Natural Sciences Area|Neuroscience*|Physics*|Physics and Astronomy|Scientific Computing|Statistics&#39;,
      social_science_majors: &#39;Economics*|Economics–Statistics|History*|Political Science*|Politics-Philosophy|Psychology|Sociology*|Urban Studies&#39;,
      humanities_majors: &#39;Africana Studies*|Africana Studies–English|Anthropology|Chinese*|Classics*|English Literature*|English Writing|Film Studies*|French*|German|History of Art &amp; Architecture|Humanities Area|Italian*|Italian Studies|Japanese*|Liberal Studies|Music*|Philosophy*|Religious Studies*|Russian|Slavic Studies|Spanish|Studio Arts*|Theatre Arts*&#39;,
      business_majors: &#39;Accounting|Finance|General Management|Global Management|Marketing&#39;,
      engineering_majors: &#39;Bioengineering*|Chemical Engineering*|Civil Engineering*|Computer Engineering|Electrical Engineering*|Engineering Physics|Industrial Engineering*|Materials Science and Engineering*|Mechanical Engineering*&#39;,
      professional_majors: &#39;Administration of Justice*|Applied Developmental Psychology|Architectural Studies|Athletic Training|Clinical Dietetics and Nutrition|Communication: Rhet &amp; Comm|Communication Science|Dental Hygiene|Emergency Medicine|Health Information Management|Health Services|Health and Physical Activity|Information Science|Legal Studies*|Media and Professional Communications|Nursing|Pharmacy|Public Service*|Rehabilitation Science|Social Work*&#39;
	)
    else
      # handle validation errors
    end

    @college= College.find_or_create_by_name!(&#39;Harvard&#39;)
    if @college.update_attributes(
      url: &#39;harvard&#39;,
      public: &#39;Private&#39;,
      years: &#39;4-year&#39;,
      category: &#39;National University&#39;,
      calendar: &#39;Semester&#39;,
      location: &#39;Cambridge, MA&#39;,
      setting: &#39;Small City (50-250k)&#39;,
      degrees: &#39;Bachelors, Masters, Doctoral&#39;,
      rotc: &#39;Air Force, Army, Navy&#39;,
      considered: &#39;Academic GPA|Alumni Relation|Application Essay|Character/Personal Qualities|Extracurricular Activities|First Generation College Student|Geographical Residence|Interview|Racial/Ethnic Status|Recommendations|Rigor of secondary school record|Standardized Test Scores|Talent/Ability|Volunteer Work|Work Experience&#39;,
      student_faculty: &#39;7 to 1&#39;)
    else
      # handle validation errors
    end

I left out all the other colleges. I have 200 schools so far, but Pitt is the only one with comprehensive data so far.  The rest just have basic data, like Harvard.  I also left out some of the data for Pitt for the sake of brevity, but let me know if you&#39;d like me to include the rest.

Edit: I tried taking out the `*`&#39;s in `science_majors` on down and then running `rake db:seed`, but that didn&#39;t change anything.

Rails: Invalid byte sequence in US-ASCII (Argument Error) when I run rake db:seed

What is rake and how it is used in Ruby on Rails?

What is rake and how it is used in rails?

I am running Rails 3.2.3, Ruby 1.9 under Fedora 17.  I get this warning, when I run `rails s`, and how do I fix?

&gt;    SECURITY WARNING: No secret option provided to Rack::Session::Cookie.
&gt;    This poses a security threat. It is strongly recommended that you
&gt;    provide a secret to prevent exploits that may be possible from crafted
&gt;    cookies. This will not be supported in future versions of Rack, and
&gt;    future versions will even invalidate your existing user cookies.

No secret option provided to Rack::Session::Cookie warning?

I&#39;m trying to follow instructions from the book &quot;Head First Rails&quot; and on page 50 it says to create a model but I am unable to create a model using the rails command.

When I type this at this prompt: localhost:~ home$

     rails generate model ad name:string description:text price:decimal seller_id:integer email:string img_url:string

I get this:

    Usage:
      rails new APP_PATH [options]
    
    Options:
      -r, [--ruby=PATH]              # Path to the Ruby binary of your choice
                                     # Default: /Users/home/.rvm/rubies/ruby-1.9.3-p125/bin/ruby
      -b, [--builder=BUILDER]        # Path to a application builder (can be a filesystem path or URL)
      -m, [--template=TEMPLATE]      # Path to an application template (can be a filesystem path or URL)
          [--skip-gemfile]           # Don&#39;t create a Gemfile
          [--skip-bundle]            # Don&#39;t run bundle install
      -G, [--skip-git]               # Skip Git ignores and keeps
      -O, [--skip-active-record]     # Skip Active Record files
      -S, [--skip-sprockets]         # Skip Sprockets files
      -d, [--database=DATABASE]      # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db/sqlserver/jdbcmysql/jdbcsqlite3/jdbcpostgresql/jdbc)
                                     # Default: sqlite3
      -j, [--javascript=JAVASCRIPT]  # Preconfigure for selected JavaScript library
                                     # Default: jquery
      -J, [--skip-javascript]        # Skip JavaScript files
          [--dev]                    # Setup the application with Gemfile pointing to your Rails checkout
          [--edge]                   # Setup the application with Gemfile pointing to Rails repository
      -T, [--skip-test-unit]         # Skip Test::Unit files
          [--old-style-hash]         # Force using old style hash (:foo =&gt; &#39;bar&#39;) on Ruby &gt;= 1.9
    
    Runtime options:
      -f, [--force]    # Overwrite files that already exist
      -p, [--pretend]  # Run but do not make any changes
      -q, [--quiet]    # Suppress status output
      -s, [--skip]     # Skip files that already exist
    
    Rails options:
      -h, [--help]     # Show this help message and quit
      -v, [--version]  # Show Rails version number and quit
    
    Description:
        The &#39;rails new&#39; command creates a new Rails application with a default
        directory structure and configuration at the path you specify.
    
        You can specify extra command-line arguments to be used every time
        &#39;rails new&#39; runs in the .railsrc configuration file in your home directory.
    
        Note that the arguments specified in the .railsrc file don&#39;t affect the
        defaults values shown above in this help message.
    
    Example:
        rails new ~/Code/Ruby/weblog
    
        This generates a skeletal Rails installation in ~/Code/Ruby/weblog.
        See the README in the newly created application to get going.
    localhost:~ home$ 

I am using Rails -v 3.2.8
and Ruby 1.9.3p125

rails generate model

I have a download link in my app from which users should be able to download files which are stored on s3. These files will be publicly accessible on urls which look something like

    https://s3.amazonaws.com/:bucket_name/:path/:to/:file.png

The download link hits an action in my controller:

    class AttachmentsController &lt; ApplicationController
      def show
        @attachment = Attachment.find(params[:id])
        send_file(@attachment.file.url, disposition: &#39;attachment&#39;)
      end
    end

But I get the following error when I try to download a file:

    ActionController::MissingFile in AttachmentsController#show
    
    Cannot read file https://s3.amazonaws.com/:bucket_name/:path/:to/:file.png
    Rails.root: /Users/user/dev/rails/print
    
    Application Trace | Framework Trace | Full Trace
    app/controllers/attachments_controller.rb:9:in `show&#39;

The file definitely exists and is publicly accessible at the url in the error message.

How do I allow users to download S3 files?

Using send_file to download a file from Amazon S3?

I want to display a label in `form_for`:

    &lt;div class=&quot;field&quot;&gt;
      &lt;%= f.label :name %&gt;&lt;br /&gt;
      &lt;%= f.text_field :name %&gt;
    &lt;/div&gt;

This generates the label &quot;Name&quot;, but I want it to be &quot;Your Name&quot;. How can I change it?

Rails: Custom text for rails form_for label

I have a link that I need to submit a post request with. Normally, I&#39;d use jQuery and prevent the link&#39;s default behavior and then submit a form to the destination. This seems like something Rails should be able to help me out with. Sure enough, the `link_to` method has an option for specifying a POST http method:

    link_to &quot;Profile&quot;, &#39;http://example.com/profile&#39;, method: :post

That works, but I need to add 2 parameters too. I tried:

    link_to &quot;Profile&quot;, &#39;http://example.com/profile&#39;, method: post, param1: &#39;value1&#39;, param2: &#39;value2&#39;

That just added those parameters to the `&lt;a&gt;` HTML element, but didn&#39;t submit those when clicking the link:

    &lt;a rel=&quot;nofollow&quot; param1=&quot;value1&quot; param2=&quot;value2&quot; data-method=&quot;post&quot; href=&quot;http://example.com/profile&quot;&gt;Profile&lt;/a&gt;

Is there a way to do a POST request with parameters using `link_to` or any other Rails method? I&#39;m using Rails 3.2.9.

Content Type	Original Author	Original Content on Stackoverflow
Question	Iain	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Seamus Abshere	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	localhostdotdev	View Answer on Stackoverflow

Model.reset_column_information does not reload columns in rails migration

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Solution 2 - Ruby on-Rails

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Attributions