# Strange behavior with has\_many and size **URL:** \ **Category:** Rails\ **Created:** [February 16, 2006, 12:49am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984 "2006-02-16T00:49:15Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 12:49am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/1 "2006-02-16T00:49:15Z")
Here is a “ruby script/console” session verbatim which will explain the problem. Bear in mind that nothing is changing the database behind the scenes at any time. topics is a has\_many relationship of Sponsor. > > s = Sponsor.find(3) > > =\> #\ > > s.topics.size > > =\> 1 > > > l = s.topics > > =\> [#\ > > l.size > > =\> 20 > > > s.topics.size > > =\> 20 Weird? Yes, but that’s the verbatim session. It seems that s.topics.size and l.size should return the same number (the correct number of related rows is 20). Why did s.topics.size return the correct number the second time? When I put a tail on the development log I can see the query that is being run and if I paste that into a psql window, it (always) returns 20 rows. The query is identical each time, it is just the value of size() that changes. Unfortunately the same workaround does not work in application code. If, in a view, I say this (assume a \<% for sponsor in @sponsors %\> outer loop with @sponsors set in the controller): \<%= sponsor.topics.size %\> It shows up as 1 on the page, and if I do this: \<% l = sponsor.topics %\> \<%= l.size %\> It still shows 1. This is using Ruby 1.8.2 and locomotive on Mac Os X 10.4.4 with PostgreSQL 7.4. I hesitate to post more details of the tables or the has\_many relationship because it is proprietary stuff, but if anyone wants to email me off-list I can provide more info. Thanks Dan dan at dandante dot calm without the l ---
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 12:58am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/2 "2006-02-16T00:58:05Z")
Dan T. wrote: > Here is a “ruby script/console” session verbatim which will explain the > problem… I just tried the app on a linux system and it works fine. Something is wrong with my installation on the Mac, but what? ---
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 1:03am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/3 "2006-02-16T01:03:53Z")
Dan T. wrote: > Dan T. wrote: > > > Here is a “ruby script/console” session verbatim which will explain the > > problem… > > I just tried the app on a linux system and it works fine. Something is > wrong with my installation on the Mac, but what? Sorry to keep replying to myself, but the problem occurs again on a different linux box which is supposedly running the same versions of everything as the linux box where everything works. I’m very puzzled now… ---
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 2:35am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/4 "2006-02-16T02:35:57Z")
Dan T. wrote: > Dan T. wrote: > > > Dan T. wrote: > > > > > Here is a “ruby script/console” session verbatim which will explain the > > > problem… > > > > I just tried the app on a linux system and it works fine. Something is > > wrong with my installation on the Mac, but what? > > Sorry to keep replying to myself, but the problem occurs again on a > different linux box which is supposedly running the same versions of > everything as the linux box where everything works. > > I’m very puzzled now… What happens with this? sponsor.topics.length Or, sponsor.topics.find(:all).size Very strange indeed. ---
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 3:11am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/5 "2006-02-16T03:11:27Z")
Dan T. wrote: > Chris S. wrote: > > > What happens with this? > > > > sponsor.topics.length > > That works! I had though that length() was just an alias to size() or > vice versa, now I see I’ll have to go back to the documentation and find > out the difference. Thanks! Well, strangely, size is in the documentation as the correct way to return the values. However, length works since you are getting back an array. Just out of curiosity, do you have a counter\_cache? Perhaps _that_ is being returned by the size method. > > Or, > > > > sponsor.topics.find(:all).size > > That’s not valid syntax, apparently. But it doesn’t matter because > length() works. > Thanks again. Hmm, I thought that worked… oh well :-p ---
**Author:** ![dandante](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/9fc29f/32.png) [@dandante](https://www.ruby-forum.com/u/dandante)\ **Post date:** [February 16, 2006, 2:55am UTC](https://www.ruby-forum.com/t/strange-behavior-with-has-many-and-size/68984/6 "2006-02-16T02:55:47Z")
Chris S. wrote: > What happens with this? > > sponsor.topics.length That works! I had though that length() was just an alias to size() or vice versa, now I see I’ll have to go back to the documentation and find out the difference. Thanks! > Or, > > sponsor.topics.find(:all).size That’s not valid syntax, apparently. But it doesn’t matter because length() works. Thanks again.