Filter via has_many, but show all has_many objects in result

Rails
1

I have a model, resource, which has_many categories:

has_many :category_resources, :dependent => :destroy
has_many :categories, :through => :category_resources

I have it setup to filter on categories, for a list view:
records =
Resource.includes(:categories).where(“category_resources.category_id” =>
categories)

But I want it to still show all categories for a particular resource
the
listing, rather than just what was searched on.

eg, a resource, apple, has the categories, Food, Fruit, and Red.

If you select the resource Food, it should show:
Name: Apple
Categories: [Food, Fruit, Red]

Instead, I’m just getting:
Name: Apple
Categories: [Food]

What would be the best way to structure my query for this to work?

2

On 7 March 2013 21:34, [email protected] wrote:

I have a model, resource, which has_many categories:

has_many :category_resources, :dependent => :destroy
has_many :categories, :through => :category_resources

I have it setup to filter on categories, for a list view:
records =
Resource.includes(:categories).where(“category_resources.category_id” =>
categories)

Can you explain in words what you are trying to achieve with the query
above please.

Instead, I’m just getting:
Name: Apple
Categories: [Food]

If you have a Resource in resource, then resource.categories should
always show you all the categories.

Colin

3

On Thursday, March 7, 2013 9:34:17 PM UTC, [email protected] wrote:

This use of includes combined with the condition makes rails use a join
to
do the include, but, as you’ve found the filtering then filters the
included rows, since everything is done with a single query. I’d try
something like

Resource.joins(:category_resources).where("category_resources.category_id"

=> categories).preload(:categories)

assuming that you want the proloading for performance reasons. This
splits
out the eager loading stuff from the main query.

Fred