Problem with creating a database scheme/model

rubyonrails-talk
1

Hi there,

I have a problem with creating a database scheme and the according models. To describe the situation I made small scribble, because I think that explains it best.

http://herrbuerger.com/scheme.001.jpg

So I have several pages and each page has many texts, pictures and assets. So far the models look like this:

Page has_many :texts has_many :pictures has_many :assets

Texts belongs_to :page

Picture belongs_to :page

Asset belongs_to :page

Right now i have to query each table (pictures, texts, assets) seperately to get all the stuff that belongs to ONE page.

What I want to do is just fire one query to get all the items. I really rack my brain on this one. Hopefully one of you guys can give me a hint on how to do this.

Thanks for your time, Chris

(note: I posted this to the other Rails Mailinglist, because I did not know about this one. However this list seems to be the more active one.)

2

If I understand you correctly: Personally I'd do a find_by_sql with a couple of joins in but I'm told you can use the acts_as_ferret plugin too

3

Chris-Aix wrote:

Page has_many :texts has_many :pictures has_many :assets

Texts belongs_to :page

Picture belongs_to :page

Asset belongs_to :page

Right now i have to query each table (pictures, texts, assets) seperately to get all the stuff that belongs to ONE page.

What I want to do is just fire one query to get all the items. I really rack my brain on this one. Hopefully one of you guys can give me a hint on how to do this.

p = Page.find :first p.texts, p.pictures, p.assets

If you mean that rails has to make all the queries then search on eager loading in the rails api

4

Thanks for your tips.

The first thing that came to my mind was find_by_sql, but I guess that the queries are not that easy. And, Ilan, the first solution that you recommended is like the one I use now.

And to specify my problem a little bit more I'll try to explain it a little better. Right now the (pseudo)code on the "page" looks like that: <page> get_all_texts get_all_pictures get_all_assets </page>

The thing is that these elements should come out ordered, so it look for example like this: <page> text_1 picture_2 asset_1 picture_1 </page>

I hope that explains it a little bit better.

5

ok. i read the stuff about eager loading and it helped me out a little bit.

right now i am doing something like this: page = Page.find(:first, :include => [:pictures,:assets, :texts])

so this query gets all the results i need. the problem is each of this tables has a position field and the endresult should be ordered this way. i made another scribble to explain it better.

http://herrbuerger.com/scribble_list.001.jpg

any ideas?

6

Chris-Aix wrote:

ok. i read the stuff about eager loading and it helped me out a little bit.

right now i am doing something like this: page = Page.find(:first, :include => [:pictures,:assets, :texts])

so this query gets all the results i need. the problem is each of this tables has a position field and the endresult should be ordered this way. i made another scribble to explain it better.

http://herrbuerger.com/scribble_list.001.jpg

any ideas?

irb(main):001:0> elements = => irb(main):002:0> 10.times {|n| elements << %w{text picture asset}.sort_by {rand}.shift + "_" + n.to_s} => 10 irb(main):003:0> elements.sort_by {rand} => ["picture_7", "asset_5", "text_3", "text_6", "picture_0", "picture_8", "text_2", "text_9", "picture_4", "text_1"] irb(main):004:0> elements.sort_by {|a| a.match(/_(\d+)$/)[1].to_i} => ["picture_0", "text_1", "text_2", "text_3", "picture_4", "asset_5", "text_6", "picture_7", "picture_8", "text_9"]