In Rails 2, I would have written:

    validates_uniqueness_of :zipcode, :scope =&gt; :recorded_at

In Rails 3:

    validates :zipcode, :uniqueness =&gt; {:scope =&gt; :recorded_at}

For multiple attributes:

    validates :zipcode, :uniqueness =&gt; {:scope =&gt; [:recorded_at, :something_else]}

Multiple Scope Parameters:
--------------------------

    class TeacherSchedule &lt; ActiveRecord::Base
      validates_uniqueness_of :teacher_id, :scope =&gt; [:semester_id, :class_id]
    end

http://apidock.com/rails/ActiveRecord/Validations/ClassMethods/validates_uniqueness_of

This should answer Greg&#39;s question.

Dont work for me, need to put **scope** in **plural**

&gt;  validates_uniqueness_of :teacher_id, :scope**s** =&gt; [:semester_id,
&gt; :class_id]

I guess that most factory-like methods start with `create`. But why are they called &quot;[create][1]&quot;? Why not &quot;[make][2]&quot;, &quot;[produce][3]&quot;, &quot;[build][4]&quot;, &quot;[generate][5]&quot; or something else? Is it only a matter of taste? A convention? Or is there a special meaning in &quot;create&quot;?

    createURI(...) 
    makeURI(...)
    produceURI(...)
    buildURI(...)
    generateURI(...)

Which one would you choose in general and why?


  [1]: http://dictionary.reference.com/browse/create
  [2]: http://dictionary.reference.com/browse/make
  [3]: http://dictionary.reference.com/browse/produce
  [4]: http://dictionary.reference.com/browse/build
  [5]: http://dictionary.reference.com/browse/generate

How to name factory like methods?

The following snippet is annotated with the output ([as seen on ideone.com](http://ideone.com/1z1r0)):

    print &quot;100&quot; &lt; &quot;2&quot;      # True
    print &quot;5&quot; &gt; &quot;9&quot;        # False
     
    print &quot;100&quot; &lt; 2        # False
    print 100 &lt; &quot;2&quot;        # True
     
    print 5 &gt; &quot;9&quot;          # False
    print &quot;5&quot; &gt; 9          # True

    print [] &gt; float(&#39;inf&#39;) # True
    print () &gt; []          # True

Can someone explain why the output is as such?

---

### Implementation details

* Is this behavior mandated by the language spec, or is it up to implementors?
* Are there differences between any of the major Python implementations?
* Are there differences between versions of the Python language?

How does Python 2 compare string and int? Why do lists compare as greater than numbers, and tuples greater than lists?

I use Rails 3.0.0.beta4

I want to add a validation on uniqueness on two attributes, that means that my model is valid if the couple of `&#39;recorded_at&#39;` and `&#39;zipcode&#39;` is unique.

On one attribute here is the syntax

    validates :zipcode, :uniqueness =&gt; true

thanks

rails 3 validation on uniqueness on multiple attributes

I use Rails 3.0.0.beta4
I want to add a validation on uniqueness on two attributes, that means that my model is valid if the couple of <code>'recorded_at'</code> and <code>'zipcode'</code> is unique.
On one attribute here is the syntax
<pre><code class="hljs language-ini">validates :zipcode, :uniqueness => true
</code></pre>
thanks

Can anyone give me some pointers on how I could deploy my rails app to GAE? I&#39;ve been reading about it, but it seems to be a fairly complicated task.

I tried with the `google-appengine` gem, but its not a piece of cake either.

Has there been any progress with the `DataMapper` adapter or will I need to make changes to my models?

I was hoping to see a full-detail tutorial about it, but those that I found were somewhat out-of-date.

Ruby on Rails app on Google App Engine

I was wondering if there&#39;s a way in Rails to calculate time stamp like - half a minute ago, 2 minute ago, 1 day ago etc. Something like twitter real time date stamp.

I want to know if Ruby/Rails has a built-in function for such date-time conversion?

&quot;Ago&quot; date/time functions in Ruby/Rails

I&#39;m creating a new engine for a rails 3 application. As you can guess, this engine is in the lib directory of my application.

However, i have some problems developing it. Indeed, I need to restart my server each time I change something in the engine.

Is there a way to avoid this ?

Can I force rails to completely reload the lib directory or a specific file and his requirements for each request ?

Thanks for your help :)

Ruby on Rails 3 - Reload lib directory for each request

I need an SQL statement that check if one condition is satisfied:

    SELECT * FROM my_table WHERE my_table.x=1 OR my_table.y=1

I want to do this the &#39;Rails 3&#39; way. I was looking for something like:

    Account.where(:id =&gt; 1).or.where(:id =&gt; 2)

I know that I can always fallback to sql or a conditions string. However, in my experience this often leads to chaos when combining scopes. What is the best way to do this?

Another related question, is how can describe relationship that depends on an OR condition. The only way I found:

    has_many :my_thing, :class_name =&gt; &quot;MyTable&quot;,  :finder_sql =&gt; &#39;SELECT my_tables.* &#39; + &#39;FROM my_tables &#39; +
    &#39;WHERE my_tables.payer_id = #{id} OR my_tables.payee_id = #{id}&#39;

However, these again breaks when used in combinations. IS there a better way to specify this?

Ruby on Rails 3 howto make &#39;OR&#39; condition

You can get the `current_user`&#39;s permissions from a view or controller using `can?` in this fashion:

      &lt;% if can? :update, @article %&gt;
        &lt;%= link_to &quot;Edit&quot;, edit_article_path(@article) %&gt;
      &lt;% end %&gt;

How can I access this functionality from a model using this syntax:

    user.can?(:update, @article)

Access CanCan&#39;s `can?` method from a model

I have a textbox databound to a nullable int through code. If I erase the data from the textbox it gives me a validation error (red border around it).

Here is my binding code:

    ZipBinding = new Binding(&quot;Zip&quot;);
    ZipBinding.Source = Address;
    zipTextBox.SetBinding(TextBox.TextProperty, ZipBinding);

    public Int32? Zip { get { ... } set { ... } }


It&#39;s clearly marked as a Nullable&lt;Int32&gt; so why does WPF wanna give me a validation issue when I clear the textbox?

WPF DataBinding: Nullable Int still gets a validation error?

I&#39;m using an &#39;`&amp;`&#39; symbol with HTML5 and UTF-8 in my site&#39;s `&lt;title&gt;`. Google shows the ampersand fine on its [SERPs][1], as do all the browsers in their titles.

http://validator.w3.org is giving me this:

&gt; &amp; did not start a character reference. (&amp; probably should have been escaped as `&amp;amp;`.)

Do I really need to do `&amp;amp;`?

I&#39;m not fussed about my pages validating for the sake of validating, but I&#39;m curious to hear people&#39;s opinions on this and if it&#39;s important and why.

  [1]: https://en.wikipedia.org/wiki/Search_engine_results_page





Do I really need to encode &#39;&amp;&#39; as &#39;&amp;amp;&#39;?

I was wondering how to make it so that I could make a rule where a field is not equal to a value. Like I have a field called &#39;name&#39; so I don&#39;t want &#39;name&#39; = &#39;Your Name.&#39;

Does anybody have an idea of how to do this?
thanks for any help.

How to add a Not Equal To rule in jQuery.validation

I&#39;m using Rails&#39; accepts_nested_attributes_for method with great success, but how can I have it *not* create new records if a record already exists?

By way of example:

Say I&#39;ve got three models, Team, Membership, and Player, and each team has_many players through memberships, and players can belong to many teams.  The Team model might then accept nested attributes for players, but that means that each player submitted through the combined team+player(s) form will be created as a new player record.

How should I go about doing things if I want to only create a new player record this way if there isn&#39;t already a player with the same name?  If there *is* a player with the same name, no new player records should be created, but instead the correct player should be found and associated with the new team record.

accepts_nested_attributes_for with find_or_create?

Does rails have a validator like `validates_numericality_of` for boolean or do I need to roll my own?

Content Type	Original Author	Original Content on Stackoverflow
Question	denisjacquemin	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Christian Lescuyer	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	Ray	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	Jesus	View Answer on Stackoverflow

rails 3 validation on uniqueness on multiple attributes

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Multiple Scope Parameters:

Solution 3 - Ruby on-Rails

How does Python 2 compare string and int? Why do lists compare as greater than numbers, and tuples greater than lists?

How to name factory like methods?

Attributions