Returning last value

rubyonrails-talk
1

Hi.

I have the following controller of the update action:

[code] def update     @projeto = Projeto.find(params[:id])

    if (@projeto.update_attributes(params[:projeto]))

    ## Mesmo raciocínio utilizado no create.     @permissaoA = Permissao.find(:first, :conditions => ["usuario_id = ?", @projeto.responsavel.to_i])     @permissaoAvancado1 = Permissao.find(:first, :conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.responsavel.to_i])     if @permissaoAvancado1.nil?     ## Caso tenham excluido os usuários responsáveis, as permissões seriam nulas. Dai ele verifica se vai alterar ou criar uma permissão     if @permissaoA.nil?     @permissaoAv = Permissao.new(params[:permissao])     @permissaoAv.perfil = "Avançado"     @permissaoAv.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel.to_i])     @permissaoAv.save(params[:permissao])     end     end

    ## O mesmo que avançado     @permissaoI = Permissao.find(:first, :conditions => ["projeto_id = ? and perfil = ? and usuario_id = ?", @projeto.id, "Intermediário", @projeto.responsavel_td.to_i])     @permissoesB = Permissao.all(:conditions => ["projeto_id = ? and usuario_id = ? and perfil = ?", @projeto.id, @projeto.responsavel_td.to_i, "Básico"])     @permissaoAvancado2 = Permissao.find(:first, :conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.responsavel_td.to_i])     if @permissaoAvancado2.nil?     if @permissaoI.nil?       @permissaoIn = Permissao.new(params[:permissao]) # else # @permissaoIn = @permissaoI # end     @permissaoIn.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td.to_i])     @permissaoIn.projeto = Projeto.find(:first, :conditions => ["id = ?", @projeto.id])     @permissaoIn.perfil = "Intermediário" # if !@permissaoI.nil? # @permissaoIn.update_attributes(params[:permissao]) # else     @permissaoIn.save(params[:permissao])     if !@permissoesB.empty?       for perm in @permissoesB         perm.destroy       end     end     end     end

    @permissaoB = Permissao.find(:first, :conditions => ["projeto_id = ? and perfil = ? and usuario_id = ?", @projeto.id, "Básico", @projeto.coordenador.to_i])     @permissaoAvancado3 = Permissao.all(:conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.coordenador.to_i])     @permissoesI = Permissao.all(:conditions => ["projeto_id = ? AND usuario_id = ? AND perfil = ?", @projeto.id, @projeto.coordenador.to_i, "Intermediário"])     ## Se ele já tiver a permissao de avançado, não faz nada. Se não tiver, cria uma (sem nenhum projeto)     if @permissaoAvancado3.empty? && @permissoesI.empty? # if @permissaoB.nil?       @permissaoBa = Permissao.new(params[:permissao]) # else # @permissaoBa = @permissaoB # end     @permissaoBa.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.coordenador.to_i])     @permissaoBa.projeto = Projeto.find(:first, :conditions => ["id = ?", @projeto.id])     @permissaoBa.perfil = "Básico" # if !@permissaoB.nil? # @permissaoBa.update_attributes(params[:permissao]) # else       @permissaoBa.save(params[:permissao]) # end     end

    ## Ao editar um projeto, existe a possibilidade da alteração do responsável pela Td     ## Portanto, ele procura por todas as tarefas daquele projeto     @tarefas = Tarefa.all(:conditions => ["projeto_id = ?", @projeto.id])     ## Varre cada uma     for tarefa in @tarefas     ## Altera o campo "responsável" pelo respnsável_td recém modificado (ou não) na edição do projeto       tarefa.responsavel = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td]).nome     ## Atualiza as alterações       tarefa.update_attributes(params[:tarefa])     end         flash[:msg] = "Projeto atualizado com sucesso"         redirect_to(@projeto)    else       render :action => "edit"     end   end [/code]

It works ok, but what i wanna do is:

destroy the "permissao" of "responsavel_td" and "coordenador" BEFORE the update. in other words, if the "responsavel_td" or the "coordenador" change, i wanna to destroy the "permissao" existing for those who were before the change.

I make my self clear?

If you can't understand me, just think this way.. How can I return the value before the update?

Thanks any help.

2

Hi.

I have the following controller of the update action:

[code] def update @projeto = Projeto.find(params[:id])

if (@projeto.update_attributes(params[:projeto]))

## Mesmo raciocínio utilizado no create. @permissaoA = Permissao.find(:first, :conditions => ["usuario_id = ?", @projeto.responsavel.to_i]) @permissaoAvancado1 = Permissao.find(:first, :conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.responsavel.to_i]) if @permissaoAvancado1.nil? ## Caso tenham excluido os usuários responsáveis, as permissões seriam nulas. Dai ele verifica se vai alterar ou criar uma permissão if @permissaoA.nil? @permissaoAv = Permissao.new(params[:permissao]) @permissaoAv.perfil = "Avançado" @permissaoAv.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel.to_i]) @permissaoAv.save(params[:permissao]) end end

## O mesmo que avançado @permissaoI = Permissao.find(:first, :conditions => ["projeto_id = ? and perfil = ? and usuario_id = ?", @projeto.id, "Intermediário", @projeto.responsavel_td.to_i]) @permissoesB = Permissao.all(:conditions => ["projeto_id = ? and usuario_id = ? and perfil = ?", @projeto.id, @projeto.responsavel_td.to_i, "Básico"]) @permissaoAvancado2 = Permissao.find(:first, :conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.responsavel_td.to_i]) if @permissaoAvancado2.nil? if @permissaoI.nil? @permissaoIn = Permissao.new(params[:permissao]) # else # @permissaoIn = @permissaoI # end @permissaoIn.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td.to_i]) @permissaoIn.projeto = Projeto.find(:first, :conditions => ["id = ?", @projeto.id]) @permissaoIn.perfil = "Intermediário" # if !@permissaoI.nil? # @permissaoIn.update_attributes(params[:permissao]) # else @permissaoIn.save(params[:permissao]) if !@permissoesB.empty? for perm in @permissoesB perm.destroy end end end end

@permissaoB = Permissao.find(:first, :conditions => ["projeto_id = ? and perfil = ? and usuario_id = ?", @projeto.id, "Básico", @projeto.coordenador.to_i]) @permissaoAvancado3 = Permissao.all(:conditions => ["projeto_id = ? and usuario_id = ?", 0, @projeto.coordenador.to_i]) @permissoesI = Permissao.all(:conditions => ["projeto_id = ? AND usuario_id = ? AND perfil = ?", @projeto.id, @projeto.coordenador.to_i, "Intermediário"]) ## Se ele já tiver a permissao de avançado, não faz nada. Se não tiver, cria uma (sem nenhum projeto) if @permissaoAvancado3.empty? && @permissoesI.empty? # if @permissaoB.nil? @permissaoBa = Permissao.new(params[:permissao]) # else # @permissaoBa = @permissaoB # end @permissaoBa.usuario = Usuario.find(:first, :conditions => ["id = ?", @projeto.coordenador.to_i]) @permissaoBa.projeto = Projeto.find(:first, :conditions => ["id = ?", @projeto.id]) @permissaoBa.perfil = "Básico" # if !@permissaoB.nil? # @permissaoBa.update_attributes(params[:permissao]) # else @permissaoBa.save(params[:permissao]) # end end

## Ao editar um projeto, existe a possibilidade da alteração do responsável pela Td ## Portanto, ele procura por todas as tarefas daquele projeto @tarefas = Tarefa.all(:conditions => ["projeto_id = ?", @projeto.id]) ## Varre cada uma for tarefa in @tarefas ## Altera o campo "responsável" pelo respnsável_td recém modificado (ou não) na edição do projeto tarefa.responsavel = Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td]).nome ## Atualiza as alterações tarefa.update_attributes(params[:tarefa]) end flash[:msg] = "Projeto atualizado com sucesso" redirect_to(@projeto) else render :action => "edit" end end [/code]

It works ok, but what i wanna do is:

destroy the "permissao" of "responsavel_td" and "coordenador" BEFORE the update. in other words, if the "responsavel_td" or the "coordenador" change, i wanna to destroy the "permissao" existing for those who were before the change.

I make my self clear?

No, not to me anyway, the code and question are too complex. Try to reduce your question to to it's basic requirement. Explain what you want to do simply rather than providing large amounts of (mostly) irrelevant code that would take too much time for the reader to understand.

If you can't understand me, just think this way.. How can I return the value before the update?

That is a much simpler question, but does not make sense as a standalone question

Colin

3

I'm in edit page, ok?

I change something and then i submit and update.

What I wanna know is:

How can I return the value that exists BEFORE I update the changes? Without losing the changes.

Now am I clear?

4

Much better, though still not sure about what you mean by 'return' the value that exists... Where are you returning it from and to? If you mean that in the update action of the controller you want to access the current value of the record in the db before saving the new values, then, assuming that you are using the normal method like @record = MyModel.find(params[:id]) if @record.update_attributes(params[:sample]) Then between those two lines @record has the original values from the db. update_attributes picks up the data from params and updates the db.

Colin

5

Colin Law wrote:

Now am I clear?

Much better, though still not sure about what you mean by 'return' the value that exists... Where are you returning it from and to? If you mean that in the update action of the controller you want to access the current value of the record in the db before saving the new values, then, assuming that you are using the normal method like @record = MyModel.find(params[:id]) if @record.update_attributes(params[:sample]) Then between those two lines @record has the original values from the db. update_attributes picks up the data from params and updates the db.

Colin

Just a point that I've always found slightly confusing. If I've understood correctly this line..

if @record.update_attributes(params[:sample])

actually *does* the updating part, believe the if is there for error trapping and returning.

I've always struggled as to why that line starts with the word "if", am I reading it right in that the line basically does the update_attributes "if" it can? Maybe I'm just thinking about it wrong but it doesn't seem intuitive to me.

6

Yes, it returns true if the save succeeds. You could have answered this yourself easily by looking at the docs.

Colin

7

I will try to put the code between those lines, thanks.

8

I've done this:

def update     @projeto = Projeto.find(params[:id])

## Here it finds one "permissao" with the user that i choose, the profile that i choose and the project that i choose.     @ex_permissaoI = Permissao.find(:first, :conditions => ["usuario_id = ? and perfil = ? and projeto_id = ?", Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td.to_i]), "Intermediário", @projeto.id])     @ex_permissaoB = Permissao.find(:first, :conditions => ["usuario_id = ? and perfil = ? and projeto_id = ?", Usuario.find(:first, :conditions => ["id = ?", @projeto.coordenador.to_i]), "Intermediário", @projeto.id]) ## Here it should destroy those "permissao"     @ex_permissaoI.destroy     @ex_permissaoB.destroy

    if (@projeto.update_attributes(params[:projeto])) (...) end

And I get this error:

You have a nil object when you didn't expect it! You might have expected an instance of ActiveRecord::Base. The error occurred while evaluating nil.destroy

9

Bla ... wrote:

I've done this:

def update     @projeto = Projeto.find(params[:id])

## Here it finds one "permissao" with the user that i choose, the profile that i choose and the project that i choose.     @ex_permissaoI = Permissao.find(:first, :conditions => ["usuario_id = ? and perfil = ? and projeto_id = ?", Usuario.find(:first, :conditions => ["id = ?", @projeto.responsavel_td.to_i]), "Intermediário", @projeto.id])     @ex_permissaoB = Permissao.find(:first, :conditions => ["usuario_id = ? and perfil = ? and projeto_id = ?", Usuario.find(:first, :conditions => ["id = ?", @projeto.coordenador.to_i]), "Intermediário", @projeto.id]) ## Here it should destroy those "permissao"     @ex_permissaoI.destroy     @ex_permissaoB.destroy

    if (@projeto.update_attributes(params[:projeto])) (...) end

And I get this error:

You have a nil object when you didn't expect it! You might have expected an instance of ActiveRecord::Base. The error occurred while evaluating nil.destroy

Well, which @ex_permissao is the nil one? Obviously, one or both of your finds are failing. You should try running that code in irb to make sure that the conditions you are constructing are actually returning something.

10

bingo bob wrote: [...]

Just a point that I've always found slightly confusing. If I've understood correctly this line..

if @record.update_attributes(params[:sample])

actually *does* the updating part, believe the if is there for error trapping and returning.

I've always struggled as to why that line starts with the word "if", am I reading it right in that the line basically does the update_attributes "if" it can? Maybe I'm just thinking about it wrong but it doesn't seem intuitive to me.

You are indeed thinking about it completely wrong. Think in the general case about how if EXPR works in Ruby: it evaluates EXPR and then looks to see if it returns true or false. So if x > 5 evaluates x > 5 and checks its return value.

Likewise, if @record.update_attributes(params[:sample]) evaluates @record.update_attributes(params[:sample]) and checks its return value. It *happens* that in the course of the evaluation, a database operation is attempted, but that's immaterial to the if statement.

Best,

11

Marnen,

that makes an awful lot of things more clear - thanks for taking the time :-).