Updating Individual database fields

[mpundu]

This is my form:

===========================
<% form_tag :action => 'update', :id => @book.id, :title => @book.title,
:price => @book.price, :description => @book.description %>
<%= render :partial => 'form' %>
<%= submit_tag 'Edit' %>
<% end %>

===========================

This is my controller code
===========================
def update

@book = Book.find(params[:id])

@book.update_attribute(:title, params[:title])
@book.update_attribute(:description, params[:description])
@book.update_attribute(:price, params[:price])


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



flash[:notice] = 'Book was successfully updated.'
redirect_to :action => 'show', :id => @book
else
render :action => 'edit'
end
end
=============================

I am trying to update only selected fields as shown in the database. Seems CRUD cant allow me. I am getting errors. How do I pass values from form fields to be used by the " @book.update_attribute". to update database fields; How can I update only selected using this method

fields in the database.

I ve struggled for a 2 weeks now. How do I go round it

[improvcornartist]

Welcome to TSDN. In the future, please use code tags when posting code. They make your code look much prettier and easier to read. See the Posting Guidelines for helpful information.

What errors are you getting when you try to update the record? What does your form partial look like?

[mpundu]

This is my form partial.


================================================== ===
<%= error_messages_for 'book' %>

<!--[form:book]-->
<p><label for="book_title">Title</label><br/>
<%= text_field 'book', 'title' %></p>

<p><label for="book_price">Price</label><br/>
<%= text_field 'book', 'price' %></p>

<p><label for="book_description">Description</label><br/>
<%= text_area 'book', 'description' %></p>

<p><label for="book_created_at">Created at</label><br/>
<%= datetime_select 'book', 'created_at' %></p>

<p><label for="book_updated_at">Updated at</label><br/>
<%= datetime_select 'book', 'updated_at' %></p>
<!--[eoform:book]-->

================================================== ===
and this the error message i get when i click on edit

================================================== ===

Showing app/views/books/edit.rhtml where line #11 raised:
compile error
C:/railsapps/library/app/views/books/edit.rhtml:11: syntax error, unexpected kEND, expecting $end

Extracted source (around line #11):
8: <%= link_to 'Show', :action => 'show', :id => @book %> |
9: <%= link_to 'Back', :action => 'list' %>

Trace of template inclusion: /app/views/books/edit.rhtml

RAILS_ROOT: ./script/../config/..
================================================== ===

[improvcornartist]

To use code tags, click the # button when posting a message.

Instead of

@book.update_attribute(:title, params[:title])

have you tried

@book.update_attribute(:title, params[:book][:title])

It might just not be getting the correct param.

You may also need to change the

<% end %>

to

</form>

The error sounds like it doesn't like the 'end' tag.

[mpundu]

Hi . I made amendments as per your advice. Here is the controller and view code.

controller

def update
 
    @book = Book.find(params[:id])
 
    if @book.update_attributes(params[:book])
 
       @book.update_attributes(params[:book][:title][:price][:description])       
       # when I remove " [:description]" above it works. 
 
        flash[:notice] = 'Book was successfully updated.'
        redirect_to :action => 'show', :id => @book
    else
      render :action => 'edit'
    end
  end
 
  def destroy
    Book.find(params[:id]).destroy
    redirect_to :action => 'list'
  end

Edit form

<h1>Editing book</h1>
 
<%= start_form_tag :action => 'update', :id => @book %>
  <%= render :partial => 'form' %>
  <%= submit_tag 'Edit' %>
<%= end_form_tag %>
 
<%= link_to 'Show', :action => 'show', :id => @book %> |
<%= link_to 'Back', :action => 'list' %>

form partial

<%= error_messages_for 'book' %>
 
<!--[form:book]-->
<p><label for="book_title">Title</label><br/>
<%= text_field 'book', 'title'  %></p>
 
<p><label for="book_price">Price</label><br/>
<%= text_field 'book', 'price'  %></p>
 
<p><label for="book_description">Description</label><br/>
<%= text_area 'book', 'description'  %></p>
 
<!--[eoform:book]-->

here is the error message I am getting

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.[]

RAILS_ROOT: ./script/../config/..

[improvcornartist]

Try the following and see what it does.

#In def update, change
@book.update_attributes(params[:book][:title][:price][:description])
#to
@book.update_attributes(params[:book][:title])
@book.update_attributes(params[:book][:price])
@book.update_attributes(params[:book][:description])