Here&#39;s a quote from the [mysql2 gem page](https://github.com/brianmario/mysql2):

&gt; Yeah… but why?
&gt; 
&gt; Someone: Dude, the Mysql gem works
&gt; fiiiiiine.
&gt; 
&gt; Me: It sure does, but it only hands
&gt; you nil and strings for field values.
&gt; Leaving you to convert them into
&gt; proper Ruby types in Ruby-land - which
&gt; is slow as balls.
&gt; 
&gt; Someone: OK fine, but do_mysql can
&gt; already give me back values with Ruby
&gt; objects mapped to MySQL types.
&gt; 
&gt; Me: Yep, but its API is considerably
&gt; more complex and can be ~2x slower.


mysql2 is very much faster than the mysql gem. Also, apart from being effective, it also has more features and is more fun, just like Ruby on Rails.


how can I reload and animate just one cell/row ?
Right now i download some files. Everytime a file finished downloading, i call it&#39;s finished delegate and call [tableview reload].
But then the whole table reloads. And how can i animate the table, so that it doesn&#39;t blink in. For example a fade effect or so.

greets Max 

How to reload and animate just one UITableView cell/row?

I want to acess all the localStorage variables saved on a specific page. How do I do that? I want to show it like I would show an array with the join() function

How can I show all the localStorage saved variables?

I used to work with the `mysql` gem, but often nowadays I hear about the `mysql2` gem. Also, it is included in the **Gemfile** by default in `Rails 3.0.x`.

What is the difference and advantages of using the `mysql2` gem?


What the difference between mysql and mysql2 gem

I used to work with the <code>mysql</code> gem, but often nowadays I hear about the <code>mysql2</code> gem. Also, it is included in the Gemfile by default in <code>Rails 3.0.x</code>.
What is the difference and advantages of using the <code>mysql2</code> gem?

How can I import an &quot;xxxx.sql&quot; dump from MySQL to a PostgreSQL database?

Import MySQL dump to PostgreSQL database

Lets say I have the table below.


I want to get all the friends, but I want the id 5 to be the first item in the list. I don&#39;t care about the order that I receive the rest of the items.

The desired query result will be:

    friends
    -------

    id    name

    5     nahum
    1     moshe
    2     haim
    3     yusuf
    4     gedalia
    6     dana
 

How can I do this?

using Mysql 5.1.x.

Thanks!

mysql SQL: specific item to be first and then to sort the rest of the items

Is there any way in MySQL to get the first 10 distinct rows of a table. 

i.e. Something like...

    SELECT TOP 10 distinct * 
    FROM people 
    WHERE names=&#39;SMITH&#39;
    ORDER BY names asc

However this method doesn&#39;t actually work, because it gives the error: &quot;Syntax Error. Missing operator in query expression distinct *&quot;

 

Select first 10 distinct rows in mysql

I&#39;ve read that Mysql server creates a log file where it keeps a record of all activities - like when and what queries execute.  

Can anybody tell me where it exists in my system? How can I read it?

Basically, I need to back up the database with different input [backup between two dates] so I think I need to use log file here, that&#39;s why I want to do it...

I think this log must be secured somehow because sensitive information such as usernames and password may be logged [if any query require this]; so may it be secured, not easily able to be seen?

I have root access to the system, how can I see the log? 

When I try to open /var/log/mysql.log it is empty.


This is my config file:

    [client]
    port        = 3306
    socket      = /var/run/mysqld/mysqld.sock

    [mysqld_safe]
    socket      = /var/run/mysqld/mysqld.sock
    nice        = 0

    [mysqld]
    log = /var/log/mysql/mysql.log 
    binlog-do-db=zero



    user        = mysql
    socket      = /var/run/mysqld/mysqld.sock
    port        = 3306
    basedir     = /usr
    datadir     = /var/lib/mysql
    tmpdir      = /tmp
    skip-external-locking

    bind-address        = 127.0.0.1
    #
    # * Fine Tuning
    #
    key_buffer      = 16M
    max_allowed_packet  = 16M
    thread_stack        = 192K
    thread_cache_size       = 8

    general_log_file        = /var/log/mysql/mysql.log
    general_log             = 1


How to see log files in MySQL?

Recently I&#39;ve learned the wonder of indexes, and performance has improved dramatically. However, with all I&#39;ve learned, I can&#39;t seem to find the answer to this question.

Indexes are great, but why couldn&#39;t someone just index all fields to make the table incredibly fast? I&#39;m sure there&#39;s a good reason to not do this, but how about three fields in a thirty-field table? 10 in a 30 field? Where should one draw the line, and why?

MySQL - why not index every field?

How can I find records in my database on a not equal condition?  I have this now, but is there a fancy rails-speak way of doing it?

    GroupUser.where(&#39;user_id != ?&#39;,me)


Rails Model find where not equal

Earlier it was working fine. I have been playing little bit config. So may be i have changed some config unknowingly.   

here is config of environment/development.rb

      config.cache_classes = false

      # Log error messages when you accidentally call methods on nil.
      config.whiny_nils = true

      # Show full error reports and disable caching
      config.consider_all_requests_local       = true
      config.action_view.debug_rjs             = true
      config.action_controller.perform_caching = false

      # Don&#39;t care if the mailer can&#39;t send
      config.action_mailer.raise_delivery_errors = false

      # Print deprecation notices to the Rails logger
      config.active_support.deprecation = :log

      # Only use best-standards-support built into browsers
      config.action_dispatch.best_standards_support = :builtin

      # migration prefix with sequence #s
      config.active_record.timestamped_migrations = false

      #time zone
      config.time_zone = &#39;UTC&#39;

Here is config section of application.rb

     # Configure the default encoding used in templates for Ruby 1.9.
     config.encoding = &quot;utf-8&quot;

     # Configure sensitive parameters which will be filtered from the log file.
     config.filter_parameters += [:password]

     config.active_record.schema_format = :sql


when i run reload! on rails console it return true

Rails Console: reload! not reflecting changes in model files? What could be possible reason?

I am trying to add an unique index that gets created from the foreign keys of four associated tables:

    add_index :studies,
      [&quot;user_id&quot;, &quot;university_id&quot;, &quot;subject_name_id&quot;, &quot;subject_type_id&quot;],
      :unique =&gt; true

The database’s limitation for the index name causes the migration to fail. Here’s the error message:

&gt; Index name &#39;index_studies_on_user_id_and_university_id_and_subject_name_id_and_subject_type_id&#39; on table &#39;studies&#39; is too long; the limit is 64 characters

How can I handle this? Can I specify a different index name?

How do I handle too long index names in a Ruby on Rails ActiveRecord migration?

I&#39;m trying to get Ruby debugger running in one of my specs:

    describe User do
      it &quot;should be valid&quot; do
        debugger
        User.new.should be_valid
      end
    end

When I run rspec though, I get:

    debugger statement ignored, use -d or --debug option to enable debugging

I&#39;ve tried the following:

    rake spec --debug
    rake spec --debug  --trace
    rake spec:models --debug
    bundle exec rspec --debug
    bundle exec rspec --debug spec/models/
    bundle exec rspec --d spec/models/
    bundle exec &quot;rspec --debug&quot; spec/models/
    bundle exec rspec --debugger spec/models/
    bundle exec --debugger rspec spec/models/
    bundle --debugger exec rspec spec/models/
    bundle --debugger exec rspec spec/models/
    bundle exec --debugger rspec spec/models/
    bundle exec rspec --debugger spec/models/

Any ideas on how to exec rspec in the right way?  I&#39;m on Rails 3.0.5, Ruby 1.9.2, RSpec 2.5.1, ruby-debug19.

Thanks,
Justin.


Running ruby debug in rspec?

The following `attempt_login` method is called using Ajax after a login form is submitted.

    class AccessController &lt; ApplicationController
      [...]
      def attempt_login
        authorized_user = User.authenticate(params[:username], params[:password])
        
        if authorized_user
          session[:user_id] = authorized_user.id
          session[:username] = authorized_user.username
          flash[:notice] = &quot;Hello #{authorized_user.name}.&quot;
          redirect_to(:controller =&gt; &#39;jobs&#39;, :action =&gt; &#39;index&#39;)
        else
          [...]
        end
      end
    end

The problem is that `redirect_to` doesn&#39;t work.

How would you solve this ?

Rails 3: How to &quot;redirect_to&quot; in Ajax call?

A method name can end with a question mark `?`

    def has_completed?
      return count &gt; 10
    end

but a variable name cannot.

What is the reason for that?  Isn&#39;t it convenient to have variable names ending the same way too? Given that we usually can&#39;t tell whether `foobar` is a method or a variable just by looking at the name `foobar` anyway, why the exception for the `?` case?

And how should I work with this? Maybe always to use `has` or `is` in the code?

    if process_has_completed
      ...
    end

    if user_is_using_console
      ...
    end

Why can&#39;t a variable name end with `?` while a method name can?

    arr = [1,2,1,3,5,2,4]

How can I count the array by group value with sorting? I need the following output:

    x[1] = 2  
    x[2] = 2  
    x[3] = 1  
    x[4] = 1  
    x[5] = 1


How to group by count in array without using loop

I have an array, each of whose elements is a hash with three key/value pairs:

    :phone =&gt; &quot;2130001111&quot;, :zip =&gt; &quot;12345&quot;, :city =&gt; &quot;sometown&quot;

I&#39;d like to sort the data by `zip` so all the `phone`s in the same area are together. Does Ruby have an easy way to do that? Can `will_paginate` paginate data in an array?

How to sort an array of hashes in ruby

For example:

    9 / 5  #=&gt; 1

but I expected `1.8`. How can I get the correct decimal (non-integer) result? Why is it returning `1` at all?

Why is division in Ruby returning an integer instead of decimal value?

I have a couple of gem files which I install via `gem install xx.gem`.  Can I tell Bundler to use them?  Or do I have to specify the source path?

How do I specify local .gem files in my Gemfile?

When I include a gem that I made, thanks to Bundler (version 1.0.12), in a Gemfile and then I try to bundle or to rake just like that:

  `$ rake`

I&#39;ve got this error message:

    Invalid gemspec in [/Users/zagzag/.rvm/gems/ruby-1.9.2-p180@foobar/specifications/myplugin-1.0.0.gemspec]: invalid date format in specification: &quot;2011-04-21 00:00:00.000000000Z&quot;

I&#39;m on the last Mac OS X (10.6.4), with:

    $ ruby -v
    ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.4.0]

and:

    $ gem -v
    Invalid gemspec in [/Users/zagzag/.rvm/gems/ruby-1.9.2-p180@foobar/specifications/myplugin-1.0.0.gemspec]: invalid date format in specification: &quot;2011-04-21 00:00:00.000000000Z&quot;
    1.7.2

I really don&#39;t see how to solve this issue.  Thanks for any ideas.

Invalid gemspec because of the date format in specification

I have a set of rails view helpers that I use regularly, and would like to package them up into a gem, such that I could just put a line in my Gemfile, and have the helpers accessible from my views.

   I have created gems before using Bundler, and Jeweler, however, I&#39;m not all all clear on how to organize the Rails view helpers in a gem, and include them into rails.

   I would appreciate any pointers, or links to up-to-date tutorials on how to do this for Rails 3

Thanks

Just to clarify:  The question isn&#39;t on &quot;how to create a gem&quot;.  Its &quot;how to package view helpers in a gem, so I can use them in Rails&quot;



Edit 2:
I also agree with the poster below..  A rails engine is waay too much overkill for this kind of (hopefully simple) requirement

How do I extract Rails view helpers into a gem?

I&#39;m trying to install PostgreSQL for Rails on Mac OS X 10.6. First I tried the MacPorts install but that didn&#39;t go well so I did the one-click DMG install. That seemed to work.

I suspect I need to install the PostgreSQL development packages but I have no idea how to do that on OS X.

Here&#39;s what I get when I try to do `sudo gem install pg`:

    $ sudo gem install pg
    Building native extensions.  This could take a while...
    ERROR:  Error installing pg:
    	ERROR: Failed to build gem native extension.
    
            /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
    checking for pg_config... yes
    Using config values from /Library/PostgreSQL/8.3/bin/pg_config
    checking for libpq-fe.h... yes
    checking for libpq/libpq-fs.h... yes
    checking for PQconnectdb() in -lpq... no
    checking for PQconnectdb() in -llibpq... no
    checking for PQconnectdb() in -lms/libpq... no
    Can&#39;t find the PostgreSQL client library (libpq)
    *** extconf.rb failed ***
    Could not create Makefile due to some reason, probably lack of
    necessary libraries and/or headers.  Check the mkmf.log file for more
    details.  You may need configuration options.
    
    Provided configuration options:
    	--with-opt-dir
    	--without-opt-dir
    	--with-opt-include
    	--without-opt-include=${opt-dir}/include
    	--with-opt-lib
    	--without-opt-lib=${opt-dir}/lib
    	--with-make-prog
    	--without-make-prog
    	--srcdir=.
    	--curdir
    	--ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
    	--with-pg
    	--without-pg
    	--with-pg-dir
    	--without-pg-dir
    	--with-pg-include
    	--without-pg-include=${pg-dir}/include
    	--with-pg-lib
    	--without-pg-lib=${pg-dir}/lib
    	--with-pg-config
    	--without-pg-config
    	--with-pg_config
    	--without-pg_config
    	--with-pqlib
    	--without-pqlib
    	--with-libpqlib
    	--without-libpqlib
    	--with-ms/libpqlib
    	--without-ms/libpqlib
    
    
    Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/pg-0.11.0 for inspection.
    Results logged to /Library/Ruby/Gems/1.8/gems/pg-0.11.0/ext/gem_make.out



Can&#39;t find the PostgreSQL client library (libpq)

I always worked my way around Nokogiri installation issues by following the documentation in the &quot;[Installing Nokogiri][1]&quot; tutorial.

But this time, even after installing all the dependencies, Nokogiri hasn&#39;t been installed.  I get the following error: 
    
    libxml2 is missing.  please visit &lt;http://nokogiri.org/tutorials/installing_nokogiri.html&gt;

I tried installing it by specifying the libxml2 and libxslt directories:
    
    sudo gem install nokogiri -- --with-xml2-include=/usr/include/libxml2 --with-xml2-lib=/usr/lib --with-xslt-dir=/usr/

but it returned the same error.

I followed all the other related Stack Overflow articles and none helped.  Does anyone have a solution?
  
[1]: http://nokogiri.org/tutorials/installing_nokogiri.html


Content Type	Original Author	Original Content on Stackoverflow
Question	fl00r	View Question on Stackoverflow
Solution 1 - Mysql	ALoR	View Answer on Stackoverflow
Solution 2 - Mysql	Nikhil	View Answer on Stackoverflow

What the difference between mysql and mysql2 gem

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

How can I show all the localStorage saved variables?

How to reload and animate just one UITableView cell/row?

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