Rails - Jun 2009 - Scaffolding question

I''m starting to get involved with models in rails and so I need to make
sure I understand exactly what I''m trying to do.  Let''s look
at a quick
example:

One table that I will be creating is a rushing_offense table for
football.  It has the following columns in the tables:

name (string)
games (fixnum)
carries (fixnum)
net (fixnum)
avg (float)
tds (fixnum)
ydspg (float)
wins (fixnum)
losses (fixnum)
ties (fixnum)

When I create the scaffold and setup the hash pairs the migration that
is created appears like this:

class CreateRushingOffenses < ActiveRecord::Migration
  def self.up
    create_table :rushing_offenses do |t|
      t.string :name
      t.fixnum :games
      t.fixnum :carries
      t.fixnum :net
      t.float :avg
      t.fixnum :tds
      t.float :ydspg
      t.fixnum :wins
      t.fixnum :losses
      t.fixnum :ties

      t.timestamps
    end
  end

  def self.down
    drop_table :rushing_offenses
  end
end

The question I have is regarding the column name.  I''ve looked at some
other migration templates (namely those in the authentication system)
and for the users model/migration, it shows something along the lines
of:

class CreateUsers < ActiveRecord::Migration
  def self.up
    create_table "users", :force => true do |t|
      t.column :login,                     :string, :limit => 40
      t.column :name,                      :string, :limit => 100,
:default => '''', :null => true
      t.column :email,                     :string, :limit => 100
      t.column :crypted_password,          :string, :limit => 40
      t.column :salt,                      :string, :limit => 40
      t.column :created_at,                :datetime
      t.column :updated_at,                :datetime
      t.column :remember_token,            :string, :limit => 40
      t.column :remember_token_expires_at, :datetime


    end
    add_index :users, :login, :unique => true
  end

  def self.down
    drop_table "users"
  end
end

So, should my migration be showing t.column instead of t.type?  I''m not
clear on the differences between this or how I would dictate with the
generator that a column should be forced (or even if it''s necessary).

Many thanks in advance.
-- 
Posted via http://www.ruby-forum.com/.

The first scaffold table should look like this: (not what I posted)

class CreateRushingOffenses < ActiveRecord::Migration
  def self.up
    create_table :rushing_offenses do |t|
      t.string :name
      t.integer :games
      t.integer :carries
      t.integer :net
      t.float :avg
      t.integer :tds
      t.float :ydspg
      t.integer :wins
      t.integer :losses
      t.integer :ties

      t.timestamps
    end
  end

  def self.down
    drop_table :rushing_offenses
  end
end

-- 
Posted via http://www.ruby-forum.com/.

The "integer", "string" and "float" methods are
just shorthands for
the column call using that type.

It''s also the "new way" (new since Rails 2, not that new now)
of
writing migrations. And the "timestamps" will create both a created_at
and also an updated_at column.

-
Maurício Linhares
http://alinhavado.wordpress.com/ (pt-br) |
http://codeshooter.wordpress.com/ (en)



On Fri, Jun 5, 2009 at 11:10 PM, J.
D.<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
>
> The first scaffold table should look like this: (not what I posted)
>
> class CreateRushingOffenses < ActiveRecord::Migration
>  def self.up
>    create_table :rushing_offenses do |t|
>      t.string :name
>      t.integer :games
>      t.integer :carries
>      t.integer :net
>      t.float :avg
>      t.integer :tds
>      t.float :ydspg
>      t.integer :wins
>      t.integer :losses
>      t.integer :ties
>
>      t.timestamps
>    end
>  end
>
>  def self.down
>    drop_table :rushing_offenses
>  end
> end
>
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>

Maurício Linhares wrote:
> The "integer", "string" and "float" methods
are just shorthands for
> the column call using that type.
> 
> It''s also the "new way" (new since Rails 2, not that new
now) of
> writing migrations. And the "timestamps" will create both a
created_at
> and also an updated_at column.
> 
> -
> Maur�cio Linhares
> http://alinhavado.wordpress.com/ (pt-br) |
> http://codeshooter.wordpress.com/ (en)
Thanks Mauricio - I actually like it better than having to do things a 
long way.  Anything shorter is better, IMO.  I appreciate the 
explanation.

I have one more question..

I''ve created a ruby program that actually parses raw statistics from
the
main NCAA web site, which I want to bring into my own database.

So, using the example above.. here''s an example of the parser I
created:

#== Scraper Version 1.0
#
#*Created By:* _Elricstorm_
#
# _Special thanks to Soledad Penades for his initial parse idea which I 
worked with to create the Scraper program.
# His article is located at 
http://www.iterasi.net/openviewer.aspx?sqrlitid=wd5wiad-hkgk93aw8zidbw_
#
require ''hpricot''
require ''open-uri''

# This class is used to parse and collect data out of an html element
class Scraper
  attr_accessor :url, :element_type, :clsname, :childsearch, :doc, 
:numrows
   # Define what the url is, what element type and class name we want to 
parse and open the url.
  def initialize(url, element_type, clsname, childsearch)
    @url = url
    @element_type = element_type
    @clsname = clsname
    @childsearch = childsearch
    @doc = Hpricot(open(url))
    @numrows = numrows
  end

  # Scrape data based on the type of element, its class name, and define 
the child element that contains our data
  def scrape_data

    @rows = []

    (doc/"#{@element_type}.#{@clsname}#{@childsearch}").each do |row|
      cells = []
      (row/"td").each do |cell|

          if (cell/" span.s").length > 0
                values =
(cell/"span.s").inner_html.split(''<br
/>'').collect{ |str|
                pair = str.strip.split(''='').collect{|val|
val.strip}
                Hash[pair[0], pair[1]]
              }

              if(values.length==1)
                cells << cell.inner_text.strip
              else
                cells << values.strip
              end

          elsif
              cells << cell.inner_text.strip
          end
      end
      @rows << cells
    end
    @rows.shift # Shifting removes the row containing the <th> table 
header elements.
    @rows.delete([]) # Remove any empty rows in our array of arrays.
    @numrows = @rows.length
  end

  def clean_celldata
     @rows[@numrows-1][0] = 120
  end

  # Print a joined list by row to see our results
  def print_values
    puts "Number of rows = #{numrows}."
    for i in 0..@numrows-1
      puts @rows[i].join('', '')
    end
  end

  # This method will be used to further process collected data
  def process_values
    File.open("testdata.txt", "w") do |f|
      for i in 0..@numrows-1
        f.puts @rows[i].join('', '')
      end
    end
    puts "Processing completed."
  end
end



# In our search we are supplying the website url to parse, the type of 
element (ex: table), the class name of that element
# and the child element that contains the data we wish to retrieve.
offensive_rushing = 
Scraper.new(''http://web1.ncaa.org/mfb/natlRank.jsp?year=2008&rpt=IA_teamrush&site=org'',
      ''table'', ''statstable'',
''//tr'')
offensive_rushing.scrape_data
offensive_rushing.clean_celldata
offensive_rushing.print_values
offensive_rushing.process_values

-------------

So, the other question I have is how do I tie in the mechanics of a 
regular ruby program into rails?  For instance, the ruby program I wrote 
requires hpricot..

I just need a bit of guidance (I catch on fast)..

Someone can run the program I included to see how it outputs..

-- 
Posted via http://www.ruby-forum.com/.

If crawling through the NCAA website is something that you want to
automate, as "crawl daily at 12 pm" you can create a rake task in your
Rails application that calls this code and then put the rake task to
be run as a cron job:

#ncaa_crawler.rake at /lib/tasks

rake :ncaa_crawler => :environment do
  #here goes the code that gets the NCAA data
  #and saves it into the database
end

The :environment thing tells Rake that it should load the rails
application before executing the task, so all objects defined in your
Rails application will be available, like your ActiveRecord models.

This code you have shown should be placed into a class in your
application and be called on this rake task.

-
Maurício Linhares
http://alinhavado.wordpress.com/ (pt-br) |
http://codeshooter.wordpress.com/ (en)



On Sat, Jun 6, 2009 at 12:38 AM, J.
D.<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
>
> Maurício Linhares wrote:
>> The "integer", "string" and "float"
methods are just shorthands for
>> the column call using that type.
>>
>> It''s also the "new way" (new since Rails 2, not that
new now) of
>> writing migrations. And the "timestamps" will create both a
created_at
>> and also an updated_at column.
>>
>> -
>> Maur�cio Linhares
>> http://alinhavado.wordpress.com/ (pt-br) |
>> http://codeshooter.wordpress.com/ (en)
>
> Thanks Mauricio - I actually like it better than having to do things a
> long way.  Anything shorter is better, IMO.  I appreciate the
> explanation.
>
> I have one more question..
>
> I''ve created a ruby program that actually parses raw statistics
from the
> main NCAA web site, which I want to bring into my own database.
>
> So, using the example above.. here''s an example of the parser I
created:
>
> #== Scraper Version 1.0
> #
> #*Created By:* _Elricstorm_
> #
> # _Special thanks to Soledad Penades for his initial parse idea which I
> worked with to create the Scraper program.
> # His article is located at
> http://www.iterasi.net/openviewer.aspx?sqrlitid=wd5wiad-hkgk93aw8zidbw_
> #
> require ''hpricot''
> require ''open-uri''
>
> # This class is used to parse and collect data out of an html element
> class Scraper
>  attr_accessor :url, :element_type, :clsname, :childsearch, :doc,
> :numrows
>   # Define what the url is, what element type and class name we want to
> parse and open the url.
>  def initialize(url, element_type, clsname, childsearch)
>    @url = url
>    @element_type = element_type
>    @clsname = clsname
>    @childsearch = childsearch
>    @doc = Hpricot(open(url))
>    @numrows = numrows
>  end
>
>  # Scrape data based on the type of element, its class name, and define
> the child element that contains our data
>  def scrape_data
>
>    @rows = []
>
>    (doc/"#{@element_type}.#{@clsname}#{@childsearch}").each do
|row|
>      cells = []
>      (row/"td").each do |cell|
>
>          if (cell/" span.s").length > 0
>                values =
(cell/"span.s").inner_html.split(''<br
> />'').collect{ |str|
>                pair = str.strip.split(''='').collect{|val|
val.strip}
>                Hash[pair[0], pair[1]]
>              }
>
>              if(values.length==1)
>                cells << cell.inner_text.strip
>              else
>                cells << values.strip
>              end
>
>          elsif
>              cells << cell.inner_text.strip
>          end
>      end
>      @rows << cells
>    end
>    -aITcM84lgDqWeq9yj9u0jQ@public.gmane.org # Shifting removes the row
containing the <th> table
> header elements.
>    -41eI0iGsgnvj7X7HiEpzZA@public.gmane.org([]) # Remove any empty rows in
our array of arrays.
>    @numrows = @rows.length
>  end
>
>  def clean_celldata
>     @rows[@numrows-1][0] = 120
>  end
>
>  # Print a joined list by row to see our results
>  def print_values
>    puts "Number of rows = #{numrows}."
>    for i in 0..@numrows-1
>      puts @rows[i].join('', '')
>    end
>  end
>
>  # This method will be used to further process collected data
>  def process_values
>    File.open("testdata.txt", "w") do |f|
>      for i in 0..@numrows-1
>        f.puts @rows[i].join('', '')
>      end
>    end
>    puts "Processing completed."
>  end
> end
>
>
>
> # In our search we are supplying the website url to parse, the type of
> element (ex: table), the class name of that element
> # and the child element that contains the data we wish to retrieve.
> offensive_rushing >
Scraper.new(''http://web1.ncaa.org/mfb/natlRank.jsp?year=2008&rpt=IA_teamrush&site=org'',
>      ''table'', ''statstable'',
''//tr'')
> offensive_rushing.scrape_data
> offensive_rushing.clean_celldata
> offensive_rushing.print_values
> offensive_rushing.process_values
>
> -------------
>
> So, the other question I have is how do I tie in the mechanics of a
> regular ruby program into rails?  For instance, the ruby program I wrote
> requires hpricot..
>
> I just need a bit of guidance (I catch on fast)..
>
> Someone can run the program I included to see how it outputs..
>
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>

Thanks again Mauricio, I will look into trying this out.  Is the rake 
task able to be defined periodically by a weekday?  For instance, if I 
want the job to only pull data on a Monday (is that feasible)?
-- 
Posted via http://www.ruby-forum.com/.

That''s not really related to the rake task, it''s a cron config
(i''m
guessing that you''re on Linux or some kind of OS that has the cron
utility).

You can google about cron and config it the way you want. Then cron
will call your rake task as needed.

-
Maurício Linhares
http://alinhavado.wordpress.com/ (pt-br) |
http://codeshooter.wordpress.com/ (en)

On Sat, Jun 6, 2009 at 1:13 AM, J.
D.<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
>
> Thanks again Mauricio, I will look into trying this out.  Is the rake
> task able to be defined periodically by a weekday?  For instance, if I
> want the job to only pull data on a Monday (is that feasible)?

Thanks for the information.  I have a dual-developing platform (windows 
and linux) but my host is on linux..

-- 
Posted via http://www.ruby-forum.com/.