From: Panagiotis Atmatzidis <atma@...>
Date: 2013-06-21T01:10:50+09:00
Subject: Re: Beginners problem with database and datamapper

Hello,

On 20 Ιουν 2013, at 15:09 , cristian cristian <lists@ruby-forum.com> wrote:

> Hi all!
> 
> I'm a complete beginner at this so please bear with me...I dont program
> at all but if I need to then I have been trying to use Ruby.
> 
> I made a hash with some URL's and i'm looping through this hash and
> using the  url stored there and getting some info from a site that i'm
> storing into a file. Im attaching my code. This actually works :)
> 
> Now I would like to store the information in a db table. So I would like
> to modify my code. I created an sqlite3 db with two tables called 'urls'
> and 'stats'. 'urls' have the columns 'ID','Description', 'URL' and
> 'stats' have the columns 'ID','Date','Title'.
> 
> Now, I need to connect to my database and fetch this data. I have used
> DataMapper for this.
> 
> My questions:
> Should I query the rows one by one?
> Should I query the whole table store into a hash and the loop through?
> When I fetch the row how can I get the column URL?
> 
> My working code:
> require 'rubygems'
> require 'mechanize'
> 
> url = {  "1" => "http://www.ruby-forum.com/",
>    "2" => "http://www.stackoverflow.com/",
>    "3" => "http://www.ruby-doc.org/"
>  }
> time=Time.now.strftime("%Y-%m-%d %H:%M")
> File.open("Stats_Test.txt","a+") do |vStats|
> #Loop - hash
>  url.each do |number,url|
>      agent = Mechanize.new
>      page = agent.get(url)
>      title = agent.page.title.strip
>      vStats.puts "#{time}  #{number}  #{title}\n"
>  end
> end
> 
> 
> My modified code so far:
> 
> require 'rubygems'
> require 'mechanize'
> require 'data_mapper'
> 
> #Sqlite3 connection
> DataMapper.setup(:default, 'sqlite:///Ruby/Stats/StatsDB.sqlite')
> 

-----------------
> class Url
>  include DataMapper::Resource
> end
> class Stats
>  include DataMapper::Resource
> end
-----------------

Why do you create these two classes? It's not wrong, I just don't get what are you trying to do here?

I don't see any 'properties' defined there anyway.

> 
> time=Time.now.strftime("%Y-%m-%d %H:%M")
> 
> int = 0
> num = 3
> 
> #What to do here?
> while int<num do
>   ds = Url.get(int)
>   #ds has the first row. Now how do I get the column 'URL'?

Try "Url.get.all" and "Url.get.all.class" to see what kind of object is returned.

>   agent = Mechanize.new
>   page = agent.get(ds:url) #I want to give it the url from the table
>   title = agent.page.title.strip #get the title from website
>   #write title to database table stats
>    #Havent thgought of this yet :)

http://datamapper.org/docs/create_and_destroy.html

> end
> 
> 
> Any suggestions are apreciated!
> 
> Br
> cristian
> 
> -- 
> Posted via http://www.ruby-forum.com/.
> 




Panagiotis (atmosx) Atmatzidis

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