MVC questions with rails

rubyonrails-talk
1

Hi,

    I have two doubts about the right way / place to write some

code.

    Question 1:
    I have a product and in the view I need to show a listbox with

all the categories of this product. - Option1: in the controller make " @product_categories = ProductCategori.all" and later in the view make " <%= f.collection_select(:product_category_id, @product_categories, :id, :name) %>" - Option2: in the view just write " <%= f.collection_select(:product_category_id, ProductCategori.all, :id, :name) %>"

    Question 2:   
    I need to list products with some complex logic
        - Option1: in the controller make "      @products

= Products.list(param1, param2)" and in the model "def self.list(param1, param2) " with all the options joins, where, … - Option2: Put all the logic in the controller and avoid calling the model

    Greetings
2

Hi,

I have two doubts about the right way / place to write some code\.

Question 1:
I have a product and in the view I need to show a listbox with all the

categories of this product. - Option1: in the controller make "@product_categories = ProductCategori.all" and later in the view make "<%= f.collection_select(:product_category_id, @product_categories, :id, :name) %>" - Option2: in the view just write "<%= f.collection_select(:product_category_id, ProductCategori.all, :id, :name) %>"

I would use option 1. The principle reason is that then if under some circumstances you don't want to show them all then the logic can go in the controller, leaving the view alone.

Question 2:
I need to list products with some complex logic
    \- Option1: in the controller make &quot;@products = Products\.list\(param1,

param2)" and in the model "def self.list(param1, param2)" with all the options joins, where, ... - Option2: Put all the logic in the controller and avoid calling the model

Never put logic in the controller if it can reasonably go in the model. Then if the logic changes (maybe you change a detail of how the data is stored in the database) this affects only the model and not the controller also. Rather than a simple method a scope may be more appropriate if the purpose is to select a set of records from the db. That is what scopes are for.

Colin

3

Thanks for the answer

El 02/02/2012 10:09, Colin Law escribi�:

Hi,

     I have two doubts about the right way / place to write some code.

     Question 1:      I have a product and in the view I need to show a listbox with all the categories of this product.          - Option1: in the controller make "@product_categories = ProductCategori.all" and later in the view make "<%= f.collection_select(:product_category_id, @product_categories, :id, :name) %>"          - Option2: in the view just write "<%= f.collection_select(:product_category_id, ProductCategori.all, :id, :name) %>"

I would use option 1. The principle reason is that then if under some circumstances you don't want to show them all then the logic can go in the controller, leaving the view alone.

     I agree with this point of view, but in the other side, I find myself repeating "@product_categories = ProductCategori.all" in several controllers, like "new" and "edit", and later I found that with default scaffold, after submitting, if there is an error, this assignation doesn't work well, and I don't understand exactly why (in rails 3.1.3).

     Question 2:      I need to list products with some complex logic          - Option1: in the controller make "@products = Products.list(param1, param2)" and in the model "def self.list(param1, param2)" with all the options joins, where, ...          - Option2: Put all the logic in the controller and avoid calling the model

Never put logic in the controller if it can reasonably go in the model. Then if the logic changes (maybe you change a detail of how the data is stored in the database) this affects only the model and not the controller also. Rather than a simple method a scope may be more appropriate if the purpose is to select a set of records from the db. That is what scopes are for.

     Completely agree!

Colin

Thanks for clearing it up.

4

Thanks for the answer

Hi,

I have two doubts about the right way / place to write some code\.

Question 1:
I have a product and in the view I need to show a listbox with all

the categories of this product. - Option1: in the controller make "@product_categories = ProductCategori.all" and later in the view make "<%= f.collection_select(:product_category_id, @product_categories, :id, :name) %>" - Option2: in the view just write "<%= f.collection_select(:product_category_id, ProductCategori.all, :id, :name) %>"

I would use option 1. The principle reason is that then if under some circumstances you don't want to show them all then the logic can go in the controller, leaving the view alone.

I agree with this point of view, but in the other side, I find myself repeating "@product_categories = ProductCategori.all" in several controllers, like "new" and "edit",

Put it in a before_filter specifying the actions that need it.

and later I found that with default scaffold, after submitting, if there is an error, this assignation doesn't work well, and I don't understand exactly why (in rails 3.1.3).

I think you had better ask about that in a different thread if you can't sort it out. Have you read the Rails Guide on Debugging which shows techniques for debugging your code.

Colin