# Help with :include on active record finds **URL:** \ **Category:** Rails\ **Created:** [June 6, 2008, 11:16pm UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783 "2008-06-06T23:16:38Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 6, 2008, 11:16pm UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/1 "2008-06-06T23:16:38Z")
Hi All, I am having trouble getting the :include option to work on my active record finds. They are not eager loading, adding the joins to the sql queries. Has anyone had this problem? Here is my query: ``` @cart = Cart.find_by_id(session[:cart_id], :include => ``` [:cart\_items]) This is generating the following query: SELECT \* FROM `carts` WHERE (`carts`.`id` = 23) LIMIT 1 Rails is not eager loading the cart\_items which belongs\_to cart. Does anyone know why? Thanks, Sean ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 6, 2008, 11:20pm UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/2 "2008-06-06T23:20:45Z")
> Rails is not eager loading the cart\_items which belongs\_to cart. Does anyone > know why? Don’t think it can. Not in a single query. You have one cart that has many items. You can’t return all of that in a single query unless you want to send duplicate rows for the cart for every row of the cart item. There may be right after that line in the logs a line fetching the cart items. Or Rails might not do it since it’s not possible. If I’m thinking clearly that is 🙂 ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 7, 2008, 12:17am UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/3 "2008-06-07T00:17:43Z")
Nah, that should work I think–see the “Eager Loading” section on [http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethod](http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethod) s.html I just tried this out in a toy app of my own, and was surprised to see in my log that _in addition_ to the left-join query immediately under the heading “Processing OrganizationsController#show”, there were 3 other queries that followed the heading “Rendering organizations/show”. One was triggered by (I think) this line in my view: \<% if @organization.people.count \> 0 %\> That generated a: SELECT count(\*) AS count\_all FROM `people` WHERE (people.organization\_id = 1) Then I have 2 instances of: SELECT \* FROM `organizations` WHERE (`organizations`.`id` = 1) Which I believe are caused by resolving the person.organization.name calls in the part of the view that lists the people belonging to @organization. So… not that this isn’t a bit dismaying, BUT–is there any chance that you too are looking at calls generated not by your find\_by\_id call, but by subsequent view activity? Cheers, -Roy ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 7, 2008, 12:34am UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/4 "2008-06-07T00:34:10Z")
On Jun 6, 10:15 pm, “Sean O’Hara” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi All, > I am having trouble getting the :include option to work on my active record > finds. They are not eager loading, adding the joins to the sql queries. Has > anyone had this problem? Here is my query: Eager loading in rails 2.1 changed: > **[Mixing :include and :conditions - Space Vatican](https://www.spacevatican.org/2008/4/29/include-and-conditions/)** > > We all love :include, it cuts down on the number of queries made to the database (especially when iterating over a collection) and generally makes … Fred ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 7, 2008, 12:28am UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/5 "2008-06-07T00:28:19Z")
I don’t think it has to do with view activity, because the cart and cart\_items queries are generated by a before\_filter… and the are only run once. Plus, they are instantiating the @cart and it’s .cart\_items children, so I don’t think any view methods would affect that. Maybe in your case you can call @organization.people.size to avoid the sql. There are other finds in my site that aren’t generating the eager loading queries like I would expect (and I believe rails used to, prior to rails 2.0.2). Here’s the kind of query I would expect rails to generated based on the find statement: mysql\> select \* from carts LEFT OUTER JOIN cart\_items ON carts.id = cart\_items.cart\_id WHERE carts.id = 23; ±—±--------------------±--------------------±-----±--------±-----------±----------±---------+ | id | created\_at | updated\_at | id | cart\_id | product\_id | option\_id | quantity | ±—±--------------------±--------------------±-----±--------±-----------±----------±---------+ | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 60 | 23 | 929 | NULL | 1 | | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 61 | 23 | 933 | NULL | 1 | | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 62 | 23 | 938 | NULL | 1 | ±—±--------------------±--------------------±-----±--------±-----------±----------±---------+ 3 rows in set (0.01 sec) I’m pretty sure rails used to do this. I find it strange that it no longer does. Thanks for the suggestions. ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 7, 2008, 12:44am UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/6 "2008-06-07T00:44:10Z")
Ah–you’re right about changing .count to .size. That does dissappear the count(\*) query. Thanks! Like I say–I do get the LEFT JOIN query. It’s not as pretty as yours, but it’s there: SELECT `organizations`.`id` AS t0\_r0, `organizations`.`name` AS t0\_r1, `organizations`.`abbreviation` AS t0\_r2, `organizations`.`city` AS t0\_r3, `organizations`.`state` AS t0\_r4, `organizations`.`crn_site` AS t0\_r5, `organizations`.`created_at` AS t0\_r6, `organizations`.`updated_at` AS t0\_r7, `people`.`id` AS t1\_r0, `people`.`first_name` AS t1\_r1, `people`.`last_name` AS t1\_r2, `people`.`birth_date` AS t1\_r3, `people`.`organization_id` AS t1\_r4, `people`.`created_at` AS t1\_r5, `people`.`updated_at` AS t1\_r6 FROM `organizations` LEFT OUTER JOIN `people` ON people.organization\_id = organizations.id WHERE (`organizations`.`id` = ‘1’) That’s with rails 2.0.2 and mysql. What’s your version & db? (There’s no chance that you left off the ‘has\_many :cart\_items’ declaration in your cart class is there?) * * * From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Sean O’Hara Sent: Friday, June 06, 2008 3:27 PM To: removed\_email\_address@domain.invalid Subject: [Rails] Re: help with :include on active record finds I don’t think it has to do with view activity, because the cart and cart\_items queries are generated by a before\_filter… and the are only run once. Plus, they are instantiating the @cart and it’s .cart\_items children, so I don’t think any view methods would affect that. Maybe in your case you can call @organization.people.size to avoid the sql. There are other finds in my site that aren’t generating the eager loading queries like I would expect (and I believe rails used to, prior to rails 2.0.2). Here’s the kind of query I would expect rails to generated based on the find statement: mysql\> select \* from carts LEFT OUTER JOIN cart\_items ON carts.id = cart\_items.cart\_id WHERE carts.id = 23; ±—±--------------------±--------------------±-----±--------±---- -------±----------±---------+ | id | created\_at | updated\_at | id | cart\_id | product\_id | option\_id | quantity | ±—±--------------------±--------------------±-----±--------±---- -------±----------±---------+ | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 60 | 23 | 929 | NULL | 1 | | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 61 | 23 | 933 | NULL | 1 | | 23 | 2008-06-06 16:13:17 | 2008-06-06 16:13:17 | 62 | 23 | 938 | NULL | 1 | ±—±--------------------±--------------------±-----±--------±---- -------±----------±---------+ 3 rows in set (0.01 sec) I’m pretty sure rails used to do this. I find it strange that it no longer does. Thanks for the suggestions. On Fri, Jun 6, 2008 at 6:16 PM, Pardee, Roy [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Nah, that should work I think–see the “Eager Loading” section on [http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethod](http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethod) s.html \<[http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMetho](http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMetho) ds.html\> I just tried this out in a toy app of my own, and was surprised to see in my log that _in addition_ to the left-join query immediately under the heading “Processing OrganizationsController#show”, there were 3 other queries that followed the heading “Rendering organizations/show”. One was triggered by (I think) this line in my view: \<% if @organization.people.count \> 0 %\> That generated a: SELECT count(\*) AS count\_all FROM `people` WHERE (people.organization\_id = 1) Then I have 2 instances of: SELECT \* FROM `organizations` WHERE (`organizations`.`id` = 1) Which I believe are caused by resolving the person.organization.name calls in the part of the view that lists the people belonging to @organization. So… not that this isn’t a bit dismaying, BUT–is there any chance that you too are looking at calls generated not by your find\_by\_id call, but by subsequent view activity? Cheers, -Roy -----Original Message----- From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Philip Hallstrom Sent: Friday, June 06, 2008 2:20 PM To: removed\_email\_address@domain.invalid Subject: [Rails] Re: help with :include on active record finds > Hi All, > I am having trouble getting the :include option to work on my > active > record finds. They are not eager loading, adding the joins to > the sql > queries. Has anyone had this problem? Here is my query: > > @cart = Cart.find\_by\_id(session[:cart\_id], :include =\> > [:cart\_items]) > > This is generating the following query: SELECT \* FROM `carts` > WHERE > (`carts`.`id` = 23) LIMIT 1 > > Rails is not eager loading the cart\_items which belongs\_to > cart. Does > anyone know why? Don’t think it can. Not in a single query. You have one cart that has many items. You can’t return all of that in a single query unless you want to send duplicate rows for the cart for every row of the cart item. There may be right after that line in the logs a line fetching the cart items. Or Rails might not do it since it’s not possible. If I’m thinking clearly that is 🙂 ---
**Author:** ![Sean\_OSHara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dbc845/32.png) [@Sean\_OSHara](https://www.ruby-forum.com/u/Sean_OSHara)\ **Post date:** [June 7, 2008, 8:15pm UTC](https://www.ruby-forum.com/t/help-with-include-on-active-record-finds/139783/7 "2008-06-07T20:15:34Z")
On 6 Jun 2008, at 22:20, Philip H. wrote: > > > > want to send duplicate rows for the cart for every row of the cart > item. That’s what Rails used to do 🙂 Fred