DB2 for Mac

É oficial. A versão GRÁTIS do DB2 está disponivel para download para mac.

Acabaram-se as desculpas do não quero outra maquina virtual para correr isso, nem sequer experimento.

Eu sei que sou suspeito para falar já que faço parte da equipa DB2. A análise que vou aqui fazer é muito influenciada pelo meu dia a dia no trabalho mas o que escrevo aqui é a minha opinião pessoal .

A IBM não trabalha no DB2 para pessoas como nós que têm uns sites jeitosos com alguns milhares de hits diários (com sorte). Eles fazem isto para aguentar soluções de escala gigante, algumas com standards pesados em  XML de agências governamentais, financeiras, health-care, etc, que transaccionam quantidades enormes de informação diáriamente. Essas empresas não só tem que minar os dados como fazer queries sobre eles de uma forma bastante intensiva. Estou a falar das maiores empresas americanas, e não o digo decor. Ouvi-o da boca de DBAs da Merrill Lynch, Barclays, ONU, Morgan Stanley, etc.. Que tem eles em comum? Todos eles usam DB2 e estão interessados em usar as funcionalidades XML do produto.

Já agora ninguém confia que seja possivel ter performance em XML certo? Bem a IBM tem pessoas inteligentes (como eu, lol) a trabalhar em tornar isso possivel. Deixo este link para vos aguçar o apetite. Claro que a performance não será a mesma que SQL mas comparado com os parsers xml que andam a usar… eheh. Exprimentem. :P

Como já descrevi o cliente normal do DB2 é facil constactar que não é feito para vender a José, ao Joaquim. Nem sequer a pequena empresa da Josefina. A versão Express-C é gratís para todos por isso mesmo. As limitações são um máximo de 16Gb de ram e 4 processadores na maquina.

Se isto parece razoavel:

DB2 for Mac Download

Depois contem como correu e se precisarem de umas dicas podem sempre entrar em contacto.

Footnote: Para os interessados se estão a desenvolver algo com um standard xml estranho  a probabilidade desse standard ser suportado pela ibm é grande e pode ser consultado aqui.

It’s official. yey! Great news :) 

Damien’s post.

I had to pleasure to be one of the hosts for NYU group visit in Hawthorn. The students were very lucky and got to see really good talks. Robert Morris presented explained why services are so important for IBM and how research applies to business. It was really an excellent spontaneous talk and it was to bad he didn’t stick around so I could talk to him about it. Then they got to see talk on Stream Processing and how to manage real time processing and analysis for quantities of data that are possible considered impossible to handle by most common people. I also managed to see Grady Booch for the first time, in second life. He also gave an great talk about the beauty of software (www.booch.com/architecture/blog/artifacts/Turing%20Lecture.ppt) and showed the potential of second life for this kind of event. By then both Robert and Grady had my curiosity set on the future in what concerns intellectual property but I guess that’s not a good subject for showing IBM to graduate students :) eheh. It finished in beauty  with Laxmi talking about the famous Genographic Project (https://www3.nationalgeographic.com/genographic). For those who still don’t know the genographic project is a joint venture between IBM and National Geographic where they try to find out more about the history of migrations using DNA. Cool!! The social aspect was also really important and I think students were happy with the feedback we gave them about IBM. By the way the lack of blog posts is mostly because Twitter is taking over all my blog post that can fit in under one hundred and something chars.

Thank you Susan for taking them while I still haven’t bought a decent camera :) I will probably have some more when Mailar decides to put them online. Maybe once he returns from SVL.

By the way doesn’t that duck look menacing? :\ More pictures? Here.

Well ever since I started working time for my blog has been less. I really dislike that as this little corner gives me a lot of joy not only in the moment of writing but also for the great joy that is sharing information and enabling others to learn new and exciting technologies. That’s one of the things I want to talk about today. The power of sharing.

Last two weeks I was contacted by people (mostly experienced people) that were using either my k-anonimity algorithm or my open source online testing system. The fact that people are using my silly scripts is rewarding enough but the networking opportunities and being a person enabler is really what thrills me the most. It’s pleasant to see people overcome their difficulties, help them learn a new technology and then seeing the final result. I hope to continue receiving your kind emails about my work. I will always have 5 minutes to help.

I think that if you are a blogger but you don’t share what your doing your missing out. Your code will vanish into some CD or will just remain in some folder, buried forever. Let your code live. Let it enable others. Let it grow. In the meantime it will help you get wherever you want. Actually I got another exciting news just for sharing. But unfortunately I cant disclose them just yet. It involves being invited to help writing a free Ruby on Rails book. Sorry, had to say it :) How cool is that?

Actually, the most boring thing about working at large corporation is the fact that you cannot share what you do. It no longer belongs to you and even if it’s ok to share it you have to follow a complex process to get authorization to do so. So no one does! Everybody is waiting to sue so you simply can’t do things that you assume would be ok. Referring a copyright brand without referring that the brand belongs to x can cost the company a significant amount (and your job :P) and they simply can’t risk it. But oh well. The least you can say is that the good things cancel that out.

I have beenworking on DB2 and I’m widely surprised by the quality of the pureXML support and overall behavior of the solution. The lack of advertising and tools that IBM distributes with DB2 doesn’t give you the same amount of trust that other better advertised and with better tools databases do. But when you get down to business you will realize that DB2 and Oracle are on a league of their own. Just talking to the clients will make you realise that they buy because other databases can’t handle the amount of information. And if you do XML, for the next 6 months at least I’m sure that DB2 will be miles ahead. How much longer will it take for companies to realize that storing xml in clobs ain’t probably the best solution? Anwser: Not much…

Oh, final note! I finally picked the theme for my masters thesis. It will be about data mining in xml databases so if you feel like you have a nice tittle suggestion for it just leave it in the comment box. It will be greatly appreciated.

Bem isto de ter uma casa sozinho dá algum trabalho extra. Já pensei em contractar uma empregada mas pobre como sou tenho mesmo que ser eu a cozinhar, lavar roupa e a loiça, limpar a casa. Pelo meio lá vou inventando os mais recentes cozinhados. No IBM Café comi um salmão com salada grelhado muito bom (já agora as Chicken Quesadillas também são algo) e hoje decidi tentar cozinhar o dito peixe. Nada difícil, apenas cebolada e um pouco de tomate cortado em cubos. Acompanhado por um daqueles arrozes que qualquer um – menos o Miguel Regedor que mete leite no arroz – consegue cozinhar. Tenho pena que o mac tire estas fotos manhosas que nem dá para ver nada de jeito.

Quem quiser a receita, deve tar pelo twitter. O habitual. Ah, comprei um Shufle. O raio do telemovel está com a bateria toda lixada e não conseguia ouvir música. Podia escrever uma review, mas já toda a gente sabe que é dos melhores produtos que a mac alguma vez fez.

Não está a funcionar? Reboot, esperar 25 minutos, usar enquanto está a carregar uns programas. Começar a trabalhar com 75% da ram ocupada e o processador com vários processos a concorrer por tempo. Bem bom..

Depois do reboot continua a não funcionar? Format. Agora já funciona! :) 75% da memoria ocupada, o java irá provavelmente crashar o computador nas próximas duas horas. Bluescreen assegurado uma vez por semana.

É isto que o pessoal chama enterprise ready. Yeah right. Montam coisas em cima de coisas sem se preocuparem com a qualidade.

Use linux! três razões (podiam ser 30 mil mas fico por aqui)

• Mais barato
• Mais fiavel
• Mais rapido
• Menos crashes
• Nenhuns reboots
• Nenhums formats
• Já alguem usou MSDOS? Não desejo isto a ninguém. É tortura.
• Tem problema? Vê o codigo e submete a fix.
• Por ultimo, e para completar esta lista de três. É MELHOR!

Obrigado é tudo.

I simply can’t believe that I forgot to post this project in my blog. Anyway if you have to deploy a multiple choice test and you feel like messing arround with Ruby on Rails and DB2 here goes the link.

Open Source Online Testing System (OSOTS)

Não é novidade para ninguém. Eu sei.

Mas nem toda a gente tem a noção exacta do medo que esta crise esta a criar nos americanos. Na Yahoo – por exemplo – já houve despedimentos. Os receios vão desde o simples perder dinheiro para as universidade dos miúdos por causa das acções, passando pelo medo da ruptura em bens essenciais como gás, comida e gasolina até ao medo de um ataque eminente devido a aparente fragilidade dos EUA perante esta crise. Certo é que, mesmo não sendo analisa, o perigo de uma possível reacção em domino é enorme. Fica o gráfico das acções das empresas de informática mais representativas (segundo a minha opinião, claro) no dia em que as acções da IBM baixaram dos 100 USD.

Bem vou exprimentar o IBM Lotus Notes para Mac OS. Se correr bem vou tentar meter a w3 a correr no mac. Já agora já testaram o software da greenhouse? Se conseguirem avisem, eu já testei em 3 browsers (firefox, ie e chrome) e não consegui.

O programa DB2 on Campus, que pretende aproximar a comunidade estudantil deste motor de base de dados da IBM, vai visitar Portugal.

Eu estive muito envolvido neste programa sendo distinguido pela IBM pelos meus esforços enquanto um dos primeiros DB2 Ambassadors Portugueses. Dois exemplos:  o desenvolvimento do OSOTS e uma demonstração sobre METS Standard with IBM DB2 Express C using XForms as user-interface and Ruby on Rails as a Rest Web-services.

Foram estes projectos que facilitaram a minha visibilidade junto de alguns IBMers, o que possibilitou que fosse contratado para trabalhar no IBM Watson Research Center em Nova Iorque. Essa é, alias, a única razão pela qual não vou estar presente. Não vou estar em Portugal.

Quem estiver interessado em bases de dados e XML, ou talvez apenas em conhecer outros IBMers, pode/deve dar um salto ao DB2 on Campus. O evento vai ser realizado em duas universidades: Universidade do Minho e Instituto Superior Técnico.

Instituto Superior Técnico (TagusPark)

• Localização
• 29 e 30 de Setembro
• Mais informações [1,2]

Universidade do Minho

• Localização
• 2 e 3 de Outubro
• Mais Informações

Foi lançado hoje a nova versão do IBM Data Studio Developer.

Desde que entrei no DB2 Students Group na condição de embaixador tive o privilégio de aprender e mexer com algumas soluções da IBM. Entre o rol de coisas que me agradaram (não vamos falar de coisas tristes, como o IBM_DB adapter para Ruby que na altura estava bastante desactualizado) foram a possibilidade de usar alojar xml nativamente na base de dados. O pureXML com suporte para XQuery foi algo que usei durante o semestre passado em projectos como o Open Source Online Testing System. O facto da LeFevre ter implementado o Mondrian no DB2 também é um ponto a favor para qualquer maluquinho da segurança dos dados. E todos tiveram a oportunidade de ver que implementei o Mondrian no ultimo semestre no âmbito da unidade curricular de criptografia e segurança de sistemas informáticos.

O Data Studio Developer é uma ferramenta para developers que usam DB2. Entre as novidades da nova versão está o suporte para PureQuery e o facto de usar o mesmo tipo de tecnologia de persistencia que a usada no Project Zero. Continuam interessados? Então podem sacar aqui.

Article: Mondrian Multidimensional K-Anonymity

Lame Ruby Implementation:

# ==================================================================================
# anonymization: group.rb
# ==================================================================================
ENVIRONMENT = 'release' #'release'

require 'set'
require 'rubygems'
require 'ruby-debug' if ENVIRONMENT == 'debug'

# ==================================================================================
# class group
#
# usage:
#  require 'group'
#
#  g = Group.new <quasi_ids>, <filename>
#  g.anonymize <k>
#
# example:
#
# lefevre.db
#
#     0             2   < -- quasi_ids
#
#   |age|  sex  | zipc | disease      |
#---+---+-------+------+--------------+--
# 0 | 25  Male    53711 Flu           |
# 1 | 25  Female  53712 Hepatitis     |
# 2 | 26  Male    53711 Bronchitis    |
# 3 | 27  Male    53710 Broken_Arm    |
# 4 | 27  Female  53712 AIDS          |
# 5 | 28  Male    53711 Hang_Nail     |
#---+---+-------+------+--------------+--
#
# irb
#  >> require 'group'
#  >> g = Group.new [0,2], 'lefevre.db'
#  >> g.anonymize 2, 'degen'
# ==================================================================================
class Group
  # create a setter method for @tuples, @filename
  # so that g.tuples = x works
  attr_writer :tuples, :filename

  @@debug = { 'best_attribute' => ENVIRONMENT == 'debug',
              'intersection'   => ENVIRONMENT == 'debug',
              'split'          => ENVIRONMENT == 'debug',
              'ordering'       => ENVIRONMENT == 'debug',
              'vars'           => ENVIRONMENT == 'debug',
              'args'           => ENVIRONMENT == 'debug'
           }
  # ================================================================================
  # to create a new group with Group.new
  # ================================================================================
  # needs to remove the full_ids from the read.
  def initialize(quasi_ids, filename, depth=0, available_ids=nil)
    # if no valid attributes are given quasi are used
    available_ids = quasi_ids if available_ids.nil?

    # initialize the instance vars
    @tuples = []
    @quasi_ids = quasi_ids
    @available_ids = available_ids
    @depth = depth

    # serves as wilcard so that no file is read on recursion
    filename == '*wc' ? @filename = nil : @filename = filename

    if @@debug['args'] and @depth == 0
      debug_puts "args : file => #{@filename}"
      debug_puts "args : k => #{@k}"
      debug_puts "args : quasi_ids => #{@quasi_ids.to_s}"
    end

    # run the read and backup procedures
    read
  end

  # ================================================================================
  # anonymization
  # ================================================================================
  def anonymize(k, heuristic='degen', partial_order=[])

    if @@debug['vars']
      #debug_puts "dvars : @tuples #{@tuples}"
      debug_puts "dvars : @available_ids #{@available_ids},"
      debug_puts "dvars : @depth #{@depth}"
    end

    # stop case
    if isnt_splittable? k
      debug_puts "dsplit: no split available for k-level #{k} with size" +
                 " #{@tuples.size}" if @@debug['split']

      # sort and generalize remaining attributes
      @available_ids.each do |attribute|
        sort attribute
        generalize attribute
      end

      # exit
      return
    end

    # where and in what attribute should we split
    # these functions have a heavy effect on the usefulness of the information
    # for the k-anonymity table
    split_attribute  = find_split_attribute @available_ids, heuristic, partial_order
    split_pos        = find_split_position split_attribute

    # create the groups for the
    # recursion
    group1 = Group.new @quasi_ids, '*wc', @depth + 1, @available_ids.clone
    group2 = Group.new @quasi_ids, '*wc', @depth + 1, @available_ids.clone

    # split at the given position
    split split_pos, group1, group2

    if split_groups_satisfy_k_anonymity?(k,group1,group2)

      debug_puts "dsplit: no more split available with attribute" +
          " #{split_attribute} (g1: #{group1.size}, g2: #{group2.size})" if @@debug['split']

      # generalize by split_attribute and then remove it from the available
      # attributes array
      generalize split_attribute
      @available_ids.delete split_attribute

      # anonymize remaining available attributes
      anonymize k, heuristic, partial_order

    else # splitting successful
      debug_puts "dsplit: splitting on attribute #{split_attribute} at" +
                 " position #{split_pos} of #{@tuples.size}" if @@debug['split']

      # assign the two groups to this instance
      @group1 = group1
      @group2 = group2

      group1.anonymize k, heuristic, partial_order
      group2.anonymize k, heuristic, partial_order

      #@tuples = []
    end
  end

  # ================================================================================
  # io and backup related
  # ================================================================================
  # read @tuples from @filename
  def read
    unless @filename.nil?
      f = File.open @filename
      f.each_line do |line|
        @tuples < < line.rstrip.split("\t\t")
      end
      f.close
    end
  end

  # reset the class to reuse
  def reset
    @available_ids  = @originally_available_ids
    @tuples = []
    read
  end

  # ================================================================================
  # overrides
  # ================================================================================
  # number of tuples
  def size
    @tuples.size
  end

  # ================================================================================
  # aux
  # ================================================================================
  # to_s

  def to_s

    str = ""

    unless @tuples.empty?
      @tuples.each do |line|
        @tuples[0].size.times { |i| str << line[i].to_s + "\t\t"}
        str << "\n"
      end
    end

    str
  end

  # shows a yaml representation of internal object
  def to_y
    require 'yaml'
    y self
  end

  private

  def debug_puts(message)
    ident=''
    @depth.times {|i| ident+="  "}
    puts ident + message
  end

  # ================================================================================
  # aux for anonymization
  # ================================================================================
  # finds the attribute with the largest range. According to LeFevre this is a good
  # heuristic to find the attribute on
  def find_split_attribute(attributes_list, heuristic, partial_order)

    debug_puts "dorder: choosing from" +
               " #{attributes_list.to_s}" if @@debug['ordering']

    best_attrib = -1
    best_attrib_count = 0.0

    attributes_list = find_minimal_elements partial_order, attributes_list

    debug_puts "dorder: minimal list is" +
               " #{attributes_list.to_s}" if @@debug['ordering']

    attributes_list.each do |attribute|
      values = @tuples.map{|t| t[attribute]}.to_set

      # degen heuristic: split on the attribute that had more degeneracy
      if heuristic == 'degen'
        if values.size < best_attrib_count or best_attrib == -1
          best_attrib = attribute
          best_attrib_count = @tuples.size.to_f / values.size.to_f
        end
      elsif heuristic == 'single'
        if values.size < best_attrib_count or best_attrib == -1
          best_attrib = attribute
          best_attrib_count = values.size
        end
      else #default
        if values.size > best_attrib_count
          best_attrib = attribute
          best_attrib_count = values.size
        end
      end
    end

    debug_puts "dbest : best atribute is #{best_attrib} with" +
               " count #{best_attrib_count}" if @@debug['best_attribute']

    return best_attrib
  end

  #  returns the position of the leftmost or rightmost median element.
  #  used to split in lhs and rhs
  def find_split_position(attribute_id)
    sort attribute_id

    median_pos = @tuples.size / 2
    median = @tuples[median_pos][attribute_id]

    split_pos_high = median_pos
    split_pos_low  = median_pos

    # split point correspond to highest index that has median value
    split_pos_high += 1 while (@tuples.size >= split_pos_high + 2) and
                              (@tuples[split_pos_high + 1][attribute_id] == median)

    high_smaller_group_size =
            [split_pos_high + 1, @tuples.size - split_pos_high - 1].min

    # split point correspond to lowest index that has median value
    split_pos_low -= 1 while (split_pos_low > 1) and
                              (@tuples[split_pos_low - 1][attribute_id] == median)

    low_smaller_group_size =
            [split_pos_low, @tuples.size - split_pos_low].min

    # choose the one with the largest group
    if high_smaller_group_size > low_smaller_group_size
      split_pos = split_pos_high
    else
      split_pos = split_pos_low - 1
    end

    return split_pos
  end

  # finds minimal elements from the list of the given attribute list according to
  # partial order specified in partial_order. partial_order contains all complete chains.
  def find_minimal_elements(partial_order, possible_elements)

    if partial_order.empty?
      debug_puts "dorder: no ordering specified" if @@debug['ordering']

      return possible_elements
    end

    # choose all possible_elements that arent in partial_order
    # those are minimal
    minimal_list = possible_elements.select { |element| !partial_order.flatten.member?(element) }

    # haskell goodies ^^
    # restrict partial_order to values in possible_elements
    restricted_partial_order = partial_order.map { |l| l.select { |element| possible_elements.member?(element) } }

    if @@debug['ordering']
      debug_puts "dorder: possible_elements list is" +
                 " #{possible_elements.to_s}"
      debug_puts "dorder: partial_order list is" +
                 " #{partial_order.to_s}"
      debug_puts "dorder: restricted_partial_order is" +
                 " #{restricted_partial_order.to_s}"
    end

   non_zero_chains = restricted_partial_order.select { |chain| not chain.empty? }

   non_zero_chains.each do |c|
     candidate = c[0]

     minimal = !restricted_partial_order.any? do |chain|
        chain.member?(candidate) and chain[0] != candidate
     end

     if minimal and not minimal_list.member?(candidate)
       minimal_list << candidate
     end
   end

   return minimal_list
  end

  # replaces attribute value with generalization that cover all tuples.
  # Expects tuples to be sorted by attribute.
  def generalize(attribute)
    min_val = @tuples[0][attribute]
    max_val = @tuples[-1][attribute]

    unless min_val == max_val
      @tuples.each do |t|
        t[attribute] = [min_val, max_val]
      end
    end

  end

  def split(split_pos, group1, group2)
    group1.tuples = @tuples[0..split_pos]
    group2.tuples = @tuples[split_pos+1..@tuples.size]
  end

  def sort(attribute)
    @tuples = @tuples.sort_by { |t| t[attribute] }
  end

  # ================================================================================
  # verbose conditions
  # ================================================================================
  def isnt_splittable?(k)
    k < 2 or group_cant_be_split_for_level?(k) or no_split_attributes_are_available?
  end

  def group_cant_be_split_for_level?(k)
    @tuples.size < 2*k
  end

  def no_split_attributes_are_available?
    @available_ids.empty?
  end

  def split_groups_satisfy_k_anonymity?(k,group1,group2)
    group1.size < k or group2.size < k
  end
end

# hack on array to display lists correctly
class Array
  def to_s
    "[" + self.join(',') + "]"
  end
end

A frase é do Lars Gustafsson, no meu livro favorito “A morte de um Apicultor”. Que com um pouco de sorte o João Moura anda a ler.

qs = Question.find_by_sql
"select X.* from ots_schema.questions," +
  "XMLTABLE (\'$d/question\' passing document as \"d\" " +
    "COLUMNS question_text VARCHAR(200)" +
    "PATH \'question_text\') as X"

qs.first.question_text.lstrip
=> "Which of the following is the correct syntax to set the DB2COMM variable to TCPIP?\n  "

If DB2 was had a good DB2 driver and a ActivePureXML (or something adapter) it would so f*ckin rock. Just look at the sample. And the dynamic nature of ruby would enable the flexibility of xml documents.

Please IBM please. DB2 for mac and decent support on Ruby. Don’t make me write things like this no more:

# Once again fixing IBM_DB bugs the ugly way
# with_scope anyone?
add_index :'ots_schema.users', :login

or

t.column :document, :xml

If your working with DB2 on Rails you probably need to check if the xml document is – at least – well formed.

I found a neat plugin called validates-xml that uses REXML to see if documents are well formed.

To install it simply

svn co http://validates-xml.googlecode.com/svn/trunk/ validates-xml-read-only

And copy that folder to vendor/plugins.

You can easily integrate schema validation with a validates_xml_with_schema method. But you should use REXML as it cames with the standard ruby bundle since version 1.8.

To use it simply restart your server and

validates_xml :xmldocument

That’s it!

Most rails developers use OS-X. Mostly because rails is built-in the latest release (Leopard) and TextMate offers a great IDE to use with Rails. Some could argue that it also works nicely on Windows but I really believe that Rails ain’t done to be used on a Windows Platform. Many articles and interviews with rails creator DHH second this statement. Rails is easy to develop in OS X and deploy in a Linux distro of your choice.

In my most recent screen-cast I explored an interesting technique of taking advantage of rails RESTful design and DB2 pureXML features to easily create a web-service that could query a relational databases with XML support (like DB2). As you must know DB2 Express-C is distributed freely and offers no limitation to home users/small companies. So it would be awesome to expand ActiveRecord to support xml elements, if a schema was provided to the database.

I’m aware that a pure xml database stategy would be a bad approach but there are situations when it simply makes sense. And in those situations one would profit greatly of two things wich are missing.

• XML Support for ActiveRecord – in construction?
• DB2 for Mac – will this ever exist?

Antonio Cangiano is creating a plugin that revolves around this concepts, but in a DB2 centered perspective. In my opinion it would be best if the rails plugin worked not only for DB2 but for any database adapter with XML support – as long as such is provided.

Let me give you a sample. Imagine that you have a database model for translating you rails application. It could be something like:

Languages

• ID, int
• DOCUMENT, XML

Imagine that the xml file is

<language isoname="pt-PT">
  <hello>Olá</hello>
  <bye>Até a próxima!</bye>
</language>
(...)

If this makes sense in your application then you could easily do something like register your model to observe (see observer design pattern) the session['language'] for changes and, if it’s changed, it would get all the XML for that language – it would fall back to default if such was not available – and create the hash with the values. The problem with this approach – besides making no sense for the internationalization problem! – is that in the observer model you would have to:

Language.find :first

And fetch the whole xml and then process it. If the XML document has 10MB, it would take some time. With XQuery support on ActiveRecord we could simply

Language.find :first,
  :xcondition => ["//language[@isoname==?]",
    session['language']]

Or, if we simply wanted to say hello in many languages – like flickr in their first page – we could simply

Language.find :first, :xcondition => '//hello'

There are just two problems that prevent rails developers from being able to do this kind of things. And those are the lack of XQuery abilities in ActiveRecord and the fact that Mac developers cannot use DB2.

HIGH QUALITY VERSION DOWNLOAD HERE

Well, here is the long promised screen-cast. The amount of topics covered is simply huge. To get you ready for the screen-cast I prepared some other more introductory screen-cast as well as some articles on these subjects. I’m sorry that I don’t have the time to document the REST, but I really advice to invest some time learning it as it’s a very pragmatic way of delivering high quality web services.

I strongly advice you to download this screen-cast from rapidshare as both Youtube and Google Videos quality is really awful. You can download it from here.

This work was really fun to do. So I hope to have the opportunity to develop it further and manage nested rest routes like /mets/1/agents to return the agents of the first submission information package (sip) using some cool DB2 pureXML features. I really feel that with a good plugin to help users take full advantage of DB2 pureXML features and a little of imagination this web-service could be of some use.

I also expect to complete the xforms model as it is not indexing a fileptr to each category when such is selected. I hope to implement this soon enough.

Here are the associated resources I developed:

• [screencast@rapidshare] METS Standard with IBM DB2 Express C using XForms as user-interface and Ruby on Rails as a Rest Web-services

• XForms
• Ruby on Rails Rest Web-Service

And here are the other two screencasts I produced to introduce you to XForms and METS:

• [screen-cast] An easy introduction to METS/XForms (The first part of the screen-cast)
• An easy introduction to METS/XForms
• [accessibility/screen-cast script] An easy introduction to METS/XForms

• [article] Installing IBM Emerging Technologies ToolKit (ETTK) on Eclipse
• [screen-cast] Create a XForms user interface from a schema using Visual XForms Designer
• [article] Some good XForms Resources
• [article] First version of the XForms without METS
• First version of the XForms without METS
  

I also advice you to take a look at this articles. All of them where very helpful to my work.

• Ubuntu work-arround for DB2 Express-C
• Starting with DB2 Express-C
• Solving problem “The database manager shared memory set cannot be allocated”
• Creating database objects & Storing validated XML data

• Ruby and DB2 Guide
• Ruby/Python and DB2 Drivers
• Getting started with DB2 and Ruby on Rails
• IBM_DB Forum

• METS: An overview and Tutorial
• METS Schema Structure Diagram

So here comes my first ever XForms sample. If you are interested in testing them out I’ll have to give you some pointers. First off all your browser probably can’t render XForms. So you need to find a specific add-on for your browser to make it work. As this XForms where made in Mozilla Firefox with this add-on I strongly recommend that you use it to get the same results. This is not my fault, XForms is not as mature as HTML or CSS and therefor these things tend to happen. You will see what I’m talking about when I get to the Know Issues! :PNow two short notes:

• For the load/save button to work you will need to change the path in the code. Just look for xforms:submission and replace the filepath for the one in your computer.
• You need to comment what’s between this for the load button to work. Why? The bind is interfering with the instance replace. How do you fix it? If i knew I would have. I think that when I do remove the bind and add the schema this behavior will be fixed..

<!– remove this lines to erase load bug. Using a schema will fix this –><!– EOB: End of bug –>

Credits for the icons go to famfamfam.Here is the list of known issues (any help is welcome):

• Not binded to the schema. That’s because I’m lasy and METS is hard work.
• xforms:select1 won’t hide the scroll on overflow:hidden. I’m not sure this is my responsibility as the add-on doesn’t represent a full XForms implementation.
• Submission not implemented. That was really not the point.
• Submission button is relevant when no authorid or workid is given. Anyone?
• Can’t style ‘add’ and ‘remove’ trigger differently from the other xforms|trigger. I tried creating a class for them having as result a weird inverted triagle. To replicate this bug you need to find a trigger and add style=”border:100px;”.

For now: that’s all folks! Have a nice week.

We use XSLT all the time to convert a XML document into another format. XML Schemas are XML documents and I think it would be interesting to create the user interface and model for that specific schema using xForms. This would drastically decrease development time and would allow a quick view on what that XML Schema is all about. In other words, this would do for xForms what JAXB does for Java.

Why xForms? xForms is W3C recommendation for creating user interfaces and it’s based on the MVC pattern. This is enough to convince me, I’m all for standards.

While researching I found some works on this subject [here, here] but they are mostly on conference proceedings and therefor I thought no one had really implemented a Generic Schema to xForms transformation engine. Before giving up I asked Vítor Rodrigues about this, as IBM is know for their XML Alphaworks. Guess what? Now I have the solution.

Here’s what you need create an xForm from a Schema:

• Download Eclipse WTP
• Open Eclipse and browse to Help > Software Updates > Find and Install
• Click New Remote Site
• Name: Emerging Technologies Toolkit (ETTK) Updates
  URL: http://awwebx04.alphaworks.ibm.com/ettktechnologies/updates
• Select it and click Finish
• Now select Emerging Technologies Toolkit (ETTK) Updates > Emerging Technologies Toolkit – Technologies > Visual XForms Designer
• Click next.
• Accept the license, install the software and restart eclipse.

Now for the Visual XForms Designer I made a little screen-cast. Just click here to see it.