# Scaffolding question

**URL:** <https://www.ruby-forum.com/t/scaffolding-question/169642>\
**Category:** Rails\
**Created:** [June 6, 2009, 4:01am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642 "2009-06-06T04:01:01Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 4:01am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/1 "2009-06-06T04:01:01Z")

</div>

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.

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 4:10am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/2 "2009-06-06T04:10:04Z")

</div>

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

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 5:31am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/3 "2009-06-06T05:31:55Z")

</div>

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/](http://alinhavado.wordpress.com/) (pt-br) |  
[http://codeshooter.wordpress.com/](http://codeshooter.wordpress.com/) (en)

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 5:47am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/4 "2009-06-06T05:47:43Z")

</div>

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/](http://alinhavado.wordpress.com/) (pt-br) |  
[http://codeshooter.wordpress.com/](http://codeshooter.wordpress.com/) (en)

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 6:13am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/5 "2009-06-06T06:13:33Z")

</div>

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)?

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 5:38am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/6 "2009-06-06T05:38:29Z")

</div>

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/](http://alinhavado.wordpress.com/) (pt-br) |  
> [http://codeshooter.wordpress.com/](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\_](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](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…

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 6:17am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/7 "2009-06-06T06:17:30Z")

</div>

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/](http://alinhavado.wordpress.com/) (pt-br) |  
[http://codeshooter.wordpress.com/](http://codeshooter.wordpress.com/) (en)

---

<div class="post-metadata">

**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [June 6, 2009, 6:20am UTC](https://www.ruby-forum.com/t/scaffolding-question/169642/8 "2009-06-06T06:20:41Z")

</div>

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