yup, looks like this:

    create_table :my_table, id: false do |t|
      t.string :key_column
      t.string :value_column
    end

just make sure to include the 
    
    id: false
part.


Is it possible to ignore changes to a file in subversion locally on one client only, without propagating the ignore to the whole repository?

The particular problem I&#39;m dealing with is that I&#39;ve checked out a project and modified a bunch of files including the Makefile, which is already part of the repository. Now the environment I&#39;m working on is different from the rest of the group, and I want the changes to the Makefiles to remain local on my machine and not be committed.

However, I don&#39;t want to set svn:ignore because that I believe would commit the ignore to the repository, while it is important to keep the make file there.

Subversion: ignore modifications to a file locally on one client only

What GUI library does Google Chrome use? 



Which GUI library does Google Chrome use?

Is it possible for me to create and use a **database table** that contains no **:id** column in ActiveRecord, Ruby on Rails.

I don&#39;t merely want to ignore the **id column**, but I wish it to be absolutely non-existent. 

    Table Example
    
    :key_column                         :value_column
    0cc175b9c0f1b6a831c399e269772661    0cc175b9c0f1b6a831c399e269772661
    4a8a08f09d37b73795649038408b5f33    0d61f8370cad1d412f80b84d143e1257
    92eb5ffee6ae2fec3ad71c777531578f    9d5ed678fe57bcca610140957afab571
    
Any more info ( like an :id_column ) would break the whole feature.

How would I implement something like this in rails?

Create an ActiveRecord database table with no :id column?

Is it possible for me to create and use a database table that contains no :id column in ActiveRecord, Ruby on Rails.
I don't merely want to ignore the id column, but I wish it to be absolutely non-existent.
<pre><code class="hljs language-ruby">Table Example

:key_column :value_column
0cc175b9c0f1b6a831c399e269772661 0cc175b9c0f1b6a831c399e269772661
4a8a08f09d37b73795649038408b5f33 0d61f8370cad1d412f80b84d143e1257
92eb5ffee6ae2fec3ad71c777531578f 9d5ed678fe57bcca610140957afab571
</code></pre>
Any more info ( like an :id_column ) would break the whole feature.
How would I implement something like this in rails?

How to restore one of my MySQL databases from `.myd`, `.myi`, `.frm` files?

How to recover MySQL database from .myd, .myi, .frm files

I have an enormous MySQL (InnoDB) database with millions of rows in the sessions table that were created by an unrelated, malfunctioning crawler running on the same server as ours. Unfortunately, I have to fix the mess now.

If I try to `truncate table sessions;` it seems to take an inordinately long time (upwards of 30 minutes). I don&#39;t care about the data; I just want to have the table wiped out as quickly as possible. Is there a quicker way, or will I have to just stick it out overnight?

Quickest way to delete enormous MySQL table

Is it crucial to close mysql connections efficiency wise, or does it automatically close after php file has run?

Is closing the mysql connection important?

For example:

    select * from tablename where fields like &quot;%string &quot;hi&quot;  %&quot;;

Error:

&gt; You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near &#39;hi&quot; &quot;&#39; at line 1

How do I build this query?


How do I escape special characters in MySQL?

There are many conflicting statements around. What is the best way to get the row count using PDO in PHP? Before using PDO, I just simply used `mysql_num_rows`.

`fetchAll` is something I won&#39;t want because I may sometimes be dealing with large datasets, so not good for my use.

Do you have any suggestions?

Row count with PDO

I am trying to create a custom rake task, but it seems I dont have access to my models. I thought this was something implicitly included with rails task.

I have the following code in lib/tasks/test.rake:

    namespace :test do
      task :new_task do
        puts Parent.all.inspect
      end
    end


And here is what my parent model looks like:

    class Parent &lt; ActiveRecord::Base
      has_many :children
    end


It&#39;s a pretty simple example, but I get the following error:

    /&gt; rake test:new_task
    (in /Users/arash/Documents/dev/soft_deletes)
    rake aborted!
    uninitialized constant Parent
    
    (See full trace by running task with --trace)


Any ideas? Thanks


Do rails rake tasks provide access to ActiveRecord models?

I find myself repeatedly looking for a clear definition of the differences of `nil?`, `blank?`, and `empty?` in Ruby on Rails.  Here&#39;s the closest I&#39;ve come:

* `blank?` objects are false, empty, or a whitespace string. For example, `&quot;&quot;`, `&quot; &quot;`, `nil`, `[]`, and `{}` are blank.

* `nil?` objects are instances of NilClass.

* `empty?` objects are class-specific, and the definition varies from class to class. A string is empty if it has no characters, and an array is empty if it contains no items.

Is there anything missing, or a tighter comparison that can be made?


How to understand nil vs. empty vs. blank in Ruby

I have the problem, that I have an migration in Rails that sets up a default setting for a column, like this example:

    def self.up
      add_column :column_name, :bought_at, :datetime, :default =&gt; Time.now
    end

Suppose, I like to drop that default settings in a later migration, how do I do that with using rails migrations?

My current workaround is the execution of a custom sql command in the rails migration, like this:

    def self.up
      execute &#39;alter table column_name alter bought_at drop default&#39;
    end

But I don&#39;t like this approach, because I am now dependent on how the underlying database is interpreting this command. In case of a change of the database this query perhaps might not work anymore and the migration would be broken. So, is there a way to express the undo of a default setting for a column in rails?

Rails migrations: Undo default setting for a column

I&#39;m looking for a way to dump the structure of an object, similar to the PHP functions `print_r` and `var_dump` for debugging reasons.




Is there a print_r or var_dump equivalent in Ruby / Ruby on Rails?

I have a Comment class with a :foreign_key of post_id in the Post class.

    class Comment &lt; ActiveRecord::Base
      belongs_to :post, :class_name =&gt; &quot;Post&quot;, :foreign_key =&gt; &quot;post_id&quot;, :counter_cache =&gt; true
      belongs_to :author, :class_name =&gt; &quot;User&quot;, :foreign_key =&gt; &quot;author_id&quot;
    end

**But my CreateComments migration does not define a database-level foreign key:**

    class CreateComments &lt; ActiveRecord::Migration
      def self.up
        create_table :comments do |t|
          t.column &quot;post_id&quot;,       :integer,   :default =&gt; 0, :null =&gt; false
          t.column &quot;author&quot;,        :string,    :default =&gt; &quot;&quot;,   :limit =&gt; 25, :null =&gt; false
          t.column &quot;author_email&quot;,  :string,    :default =&gt; &quot;&quot;,   :limit =&gt; 50, :null =&gt; false
          t.column &quot;content&quot;,       :text,      :null =&gt; false
          t.column &quot;status&quot;,        :string,    :default =&gt; &quot;&quot;,   :limit =&gt; 25, :null =&gt; false
          t.timestamps
        end
      end
    
      def self.down
        drop_table :comments
      end
    end

Instead post_id is a simple Integer column. 

**So, it seems that this foreign key relationship exists only in the mind of Rails, not at the database level.** 

Is this correct?

**Also, is it necessary for the corresponding Post model to also declare its reciprocal foreign key relationship with Comments using the :foreign_key attribute or could that be omitted?**

    class Post &lt; ActiveRecord::Base
      set_table_name(&quot;blog_posts&quot;)
      belongs_to :author, :class_name =&gt; &quot;User&quot;, :foreign_key =&gt; &#39;author_id&#39;
      has_many :comments, :class_name =&gt; &quot;Comment&quot;,
        :foreign_key =&gt; &#39;post_id&#39;, :order =&gt; &quot;created_at desc&quot;, :dependent =&gt; :destroy
      has_many :categorizations
      has_many :categories, :through =&gt; :categorizations
      named_scope :recent, :order =&gt; &quot;created_at desc&quot;, :limit =&gt; 5
      
    end



Defining foreign key relationships for Rails&#39; models

I have an array of objects in Ruby on Rails. I want to sort the array by an attribute of the object. Is it possible?


Sorting an array of objects in Ruby by object attribute?

EDIT: Please, *please*, **please** read the two requirements listed at the bottom of this post before replying. People keep posting their new gems and libraries and whatnot, which clearly don&#39;t meet the requirements.

Sometimes I want to very cheaply hack some command line options into a simple script. A fun way to do it, without dealing with getopts or parsing or anything like that, is:

    ...
    $quiet       = ARGV.delete(&#39;-d&#39;)
    $interactive = ARGV.delete(&#39;-i&#39;)
    ...
    # Deal with ARGV as usual here, maybe using ARGF or whatever.

It&#39;s not quite the normal Unix options syntax, because it will accept options non-option command line parameters, as in &quot;`myprog -i foo bar -q`&quot;, but I can live with that. (Some people, such as the Subversion developers, prefer this. Sometimes I do too.)

An option that&#39;s just present or absent can&#39;t be implemented much more simply than the above. (One assignment, one function call, one side effect.) Is there an equally simple way to deal with options that take a parameter, such as &quot;`-f` _filename_&quot;?

### EDIT:

One point I didn&#39;t make earlier on, because it hadn&#39;t become clear to me until the author of Trollop mentioned that the library fit &quot;in one [800-line] file,&quot; is that I&#39;m looking not only for clean syntax, but for a technique that has the following characteristics:

1. The entirety of the code can be included in the script file (without overwhelming the actual script itself, which may be only a couple of dozen lines), so that one can drop a single file in a `bin` dir on any system with a standard Ruby 1.8.[5-7] installation and use it. If you can&#39;t write a Ruby script that has no require statements and where the code to parse a couple of options is under a dozen lines or so, you fail this requirement.

2. The code is small and simple enough that one can remember enough of it to directly type in code that will do the trick, rather than cutting and pasting from somewhere else. Think of the situation where you&#39;re on the console of a firewalled sever with no Internet access, and you want to toss together a quick script for a client to use. I don&#39;t know about you, but (besides failing the requirement above) memorizing even the 45 lines of simplified micro-optparse is not something I care to do.

Really Cheap Command-Line Option Parsing in Ruby

    Foo = Class.new
    Foo.class_eval do
      def class_bar
        &quot;class_bar&quot;
      end
    end
    Foo.instance_eval do
      def instance_bar
        &quot;instance_bar&quot;
      end
    end
    Foo.class_bar       #=&gt; undefined method ‘class_bar’ for Foo:Class
    Foo.new.class_bar   #=&gt; &quot;class_bar&quot;
    Foo.instance_bar       #=&gt; &quot;instance_bar&quot;
    Foo.new.instance_bar   #=&gt; undefined method ‘instance_bar’ for #&lt;Foo:0x7dce8&gt;

Just based on the name of the methods, **I would expect class_eval to allow you to add a class method to Foo and instance_eval to allow you to add an instance method to Foo. But they seem to do the opposite**.

In the example above if you call class_bar on the Foo class you get an undefined method error and if you call instance_bar on the instance returned by Foo.new you also get an undefined method error. Both errors seem to contradict an intuitive understanding of what class_eval and instance_eval should do. 

**What is really the difference between these methods?**

Documentation for [class_eval][1]:

&gt; mod.class_eval(string [, filename [,
&gt; lineno]]) =&gt; obj
&gt; 
&gt; *Evaluates the string or block in the
&gt; context of mod. This can be used to
&gt; add methods to a class.*

Documentation for [instance_eval][2]:

&gt; obj.instance_eval {| | block } =&gt; obj
&gt; 
&gt; *Evaluates a string containing Ruby
&gt; source code, or the given block,
&gt; within the context of the receiver
&gt; (obj). In order to set the context,
&gt; the variable self is set to obj while
&gt; the code is executing, giving the code
&gt; access to obj’s instance variables.*


  [1]: http://www.ruby-doc.org/core-1.8.6/classes/Module.html#M001673
  [2]: http://www.rubybrain.com/api/ruby-1.8.7/doc/index.html?a=M000295&amp;name=instance_eval

How to understand the difference between class_eval() and instance_eval()?

&gt; **Possible Duplicate:**  
&gt; [Forgot Password: what is the best method of implementing a forgot password function?](https://stackoverflow.com/questions/522967/forgot-password-what-is-the-best-method-of-implementing-a-forgot-password-funct)  

&lt;!-- End of automatically inserted text --&gt;

I&#39;m programming a community website.

I want to build a &quot;forgot my password&quot; feature.

Looking around at different sites, I&#39;ve found they employ one of **three options**:

1. send the user an **email with a link to a unique, hidden URL** that allows him to change his password (Gmail and Amazon)

2. send the user an email with a **new, randomly generated password** (Wordpress)

3. send the user **his current password** (www.teach12.com)

**Option #3** seems the most convenient to the user but since I save passwords as an MD5 hash, I don&#39;t see how option #3 would be available to me since **MD5 is irreversible**. This also seems to be **insecure** option since it means that the website must be saving the password in clear text somewhere, and at the least the clear-text password is being sent over insecure e-mail to the user. Or am I missing something here?

So if I can&#39;t do option #1, **option #2** seems to be the **simplest to program** since I just have to change the user&#39;s password and send it to him. Although this is **somewhat insecure** since you have to have a live password being communicated via insecure e-mail. However, this could also be misused by trouble-makers to **pester users** by typing in random e-mails and constantly changing passwords of various users.

**Option #1** seems to be the **most secure** but requires a little extra programming to deal with a hidden URL that expires etc., but it seems to be what the big sites use.

**What experience have you had using/programming these various options? Are there any options I&#39;ve missed?**


What is the best &quot;forgot my password&quot; method?

Is a POST secure enough to send login credentials over?

Or is an SSL connection a **must**?

How secure is a HTTP POST?

I created a Web Service in .Net and so the address of the service file has a nifty auto generated explanation about how it works. When I run the page from the machine it&#39;s hosted on it even has a form that I can use to submit test values to the service. However on remote machines it hides the form and gives the message as seen above.

Is there a point to this? I&#39;ve seen other sites call this &quot;more secure&quot; but anyone could create their own forms easily making this nothing more than a nuisance if you ask me. 

&quot;The test form is only available for requests from the local machine.&quot;

I am working on a project that has to have authentication (username and password)

It also connects to a database, so I figured I would store the username and password there. However, it seems like not such a good idea to have passwords as just a text field in a table sitting on the database.


I&#39;m using C# and connecting to a 2008 express server. Can anyone suggest (with as many examples as possible) what the best way to store this type of data would be?

P.S I am open to the idea that this info not be stored in the database if a good reason can be provided

Best way to store password in database

I have a simple PHP mailer script that takes values from a form submitted via POST and mails them to me:

    &lt;?php
	$to = &quot;me@example.com&quot;;
	
	$name = $_POST[&#39;name&#39;];
	$message = $_POST[&#39;message&#39;];
	$email = $_POST[&#39;email&#39;];

	$body  =  &quot;Person $name submitted a message: $message&quot;;
	$subject = &quot;A message has been submitted&quot;;

	$headers = &#39;From: &#39; . $email;
	
	mail($to, $subject, $body, $headers);

	header(&quot;Location: http://example.com/thanks&quot;);
    ?&gt;

How can I sanitize the input?

How to sanitze user input in PHP before mailing?

I&#39;m using accepts\_nested\_attributes_for in one of my Rails models, and I want to save the children after creating the parent.

The form works perfectly, but the validation is failing. For simplicity&#39;s sake imagine the following:

    class Project &lt; ActiveRecord::Base
      has_many :tasks
      accepts_nested_attributes_for :tasks
    end

    class Task &lt; ActiveRecord::Base
      belongs_to :project

      validates_presence_of :project_id
      validates_associated :project
    end

And I am running:

    Project.create!(
      :name =&gt; &#39;Something&#39;,
      :task_attributes =&gt; [ { :name =&gt; &#39;123&#39; }, { :name =&gt; &#39;456&#39; } ]
    )

Upon saving the project model, the validation is failing on the tasks because they don&#39;t have a project_id (since the project hasn&#39;t been saved).

It seems like Rails is following the pattern below:

* Validate Project
* Validate Tasks
* Save Project
* Save Tasks

The pattern should be:

- Validate Project
- On Pass: Save Project and continue...
- Validate Tasks
  - On Pass: Save Tasks
  - On Fail: Delete Project (rollback maybe?)

So my question boils down to: How can I get Rails to run the project_id= (or project=) method and validation on the children (tasks) AFTER the parent (project) has been saved, but NOT save the parent (project) model if any child (task) is invalid?

Any ideas?

accepts_nested_attributes_for child association validation failing

I have a pretty simple HABTM set of models 

    class Tag &lt; ActiveRecord::Base 
       has_and_belongs_to_many :posts
    end 
    
    class Post &lt; ActiveRecord::Base 
       has_and_belongs_to_many :tags
       
       def tags= (tag_list) 
          self.tags.clear 
          tag_list.strip.split(&#39; &#39;).each do 
            self.tags.build(:name =&gt; tag) 
          end
       end 
    end 

Now it all works alright except that I get a ton of duplicates in the Tags table. 

What do I need to do to avoid duplicates (bases on name) in the tags table? 


has_and_belongs_to_many, avoiding dupes in the join table

I can do `Post.delete_all` to delete all my posts, but what if I want to delete all posts, comments, blogs, etc.? 

How do I iterate over all my models and run the `delete_all` method?

How to delete all data from all tables in Rails?

Should I store latitude and longitude as strings or floats (or something else)?

(I&#39;m using activerecord / ruby on rails, if that matters).

Update:

Mysql in development and postgresql in production (why does it matter?)

Content Type	Original Author	Original Content on Stackoverflow
Question	Stefan	View Question on Stackoverflow
Solution 1 - Mysql	matt	View Answer on Stackoverflow

Create an ActiveRecord database table with no :id column?

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Which GUI library does Google Chrome use?

Subversion: ignore modifications to a file locally on one client only

Attributions