Trouble getting select to work

Rails
1

I’ve tried pulling this together from examples in the book, searching
the web and this list, but so far I’ve not been able to get it working
just right.

My table is a categories table with id and category fields.

My form has the following:

<%= select('category', 'category', @categories = Category.find(:all, :order => "category").map {|cat| [cat.category, cat.category]}) %>

I used [[cat.category, cat.category] as I am not interested in the id
and want both values to be equal to the category itself.

This form is a Donation form. One of the fields in the donation record
is a category. The database does not relate these two tables. What I
want to do is simply populate the dropdown category box from the
categories table and allow a category to be selected and that category
be populated to the donation record.

In other words:

  1. Pull all categories into the form from the categories table into a
    dropdown box on adding the record
  2. Upon editing the record, again pull the categories as in step one,
    but this time cause the category selected when the record was added to
    be selected in the dropdown box, otherwise upon update the wrong
    category would be updated to the record.

The dropdown box is populated with the categories; however, when the
record is added to the database, the category field is not populated.

The log file shows the following:

e[4;35;1mCategory Load (0.078000)e[0m e[0mSELECT * FROM categories
ORDER BY category e[0m

So far so good.

And then on adding the record:

Parameters: {“commit”=>“Create”, “category”=>{“category”=>“Furniture -
Kitchen”}, “action”=>“create”,
e[4;35;1mSQL (0.062000)e[0m e[0mINSERT INTO donations
(best_contact_time, city, created_on,
item_desc, category, …

The category of “Furniture - Kitchen” is probably the eighth in the list
and is in fact the one chosen.

Two things then:

  1. Why isn’t this being updated into the database record (the field in
    the donation record is named category)

  2. Will the current code be sufficent to cause the category in the
    record to be selected upon editing of the record? Since the code in the
    form populates the dropdown box, might I need to then after that
    immediately cause the category from the record to be the selected value
    with following additonal code?

I suspect that there is no actual “selection” happening and if there
were, the donation’s record field would be populated and that would also
solve the issue when updating as well, and yet the create statement in
the log file appears to be showing a value!

Thanks for any help on this. I’ve found the dropdown boxes to be
particularly troubling.

2

Prob worth posting you model definitions but I’ve made some assumptions
about your likely models with some suggestions below:

Scott H. wrote:

I used [[cat.category, cat.category] as I am not interested in the id
and want both values to be equal to the category itself.

You may not be interested in the id, but rails will be (assuming you
have a has_many/belongs_to relationship between Category and Donation)
as this is what it will use in the category_id field in the donations
table. Assuming this is part of a Donation form you will prob benefit
from changing the select to select(‘donation’, ‘category_id’,
@categories …), depending on your models and how your controller
action will assign the category (automatically, through
Donation.new(params[:donation]), or through specific assignment
@donation = Donation.new; @donation.category =
Category.find(params[:category]); #etc

3

Chris T wrote:

Prob worth posting you model definitions but I’ve made some assumptions
about your likely models with some suggestions below:

Scott H. wrote:

I used [[cat.category, cat.category] as I am not interested in the id
and want both values to be equal to the category itself.

You may not be interested in the id, but rails will be (assuming you
have a has_many/belongs_to relationship between Category and Donation)
as this is what it will use in the category_id field in the donations
table. Assuming this is part of a Donation form you will prob benefit
from changing the select to select(‘donation’, ‘category_id’,
@categories …), depending on your models and how your controller
action will assign the category (automatically, through
Donation.new(params[:donation]), or through specific assignment
@donation = Donation.new; @donation.category =
Category.find(params[:category]); #etc

Thank you for the response Chris. It is much appreciated. I apologize
for the confusion resulting from my lack of clarity and insufficient
information surrounding the problem.

Two tables are involved here. The first is the categories table with the
following definition:

id
category

The second table is donations with the following defintion (partial):

id
item
item_desc
category (actual category and not category_id)
…

There is no relationship of 1:m or of any kind in the database or Rails.
Why? Design choice really. Only one way for categories to get into the
database: through the categories maintenance forms. The dropdown box on
the donations forms, create and update provide the only means of
category populating the donations record, and since the dropdown box on
the donations form is populated directly from the categories table,
well, the data must certainly be valid.

The scenario is that upon creating or updating a donations record, the
dropdown box is populated with categories from the categories table.

A number of things have to happen here.

  1. By default the first category retrieved from the categories table
    will be showing in the dropdown box. If say the third category is
    selected, that category of course needs to be populated in the donations
    record.

  2. When updating the donations record, again the categories are
    retrieved from the categories table, but the default category, the first
    retrieved from the categories table, must not be showing in the dropdown
    box, but instead the one in the existing donations record must be
    showing; in this scenario it would be the third category in the list.

  3. If the category is not changed, the one showing, again in this
    scenario the third one, must still be the one to populate the donations
    record upon update. And of course if the category is changed, the one
    then showing would update into the donations record.

I ran into this very same problem when doing this app using JSPs,
Hibernate and Tiles. I’d scoured the books, the internet, reading
articles and so forth for just the perfect example of how to do this. I
just could not find one that suited this same scenario, which I found
odd.

Hopefully my explanation of this problem and the database, form and
general setup is sufficient so that the resolution makes sense as well.

Of course I played around so much that I can’t even remember now what
didn’t work exactly!

The book, Agile Web D. with Rails gave me the following code
example, which provided the basis from which to begin with:

<%= User.find(:all, :order => “name”).map {|u| [u.name, u.id]}
select(:user, :name, @users)
%>

What I ended up with, and this works exactly as I had hoped for and
needed, was:

<%= select(“donation”, ‘category’, @categories = Category.find(:all,
:order => “category”).map {|cat| [cat.category, cat.category]}) %>

I didn’t use the id here from the category table records as all I really
wanted returned from the form was the category value itself which was
then populated into the donations record and table.

You however Chris did provide me with the clue I needed when you
mentioned using ‘donation’. Thank you. That led me to what I now have!