# Best Practices? - probably a newbie question

**URL:** <https://www.ruby-forum.com/t/best-practices-probably-a-newbie-question/48896>\
**Category:** Rails\
**Created:** [November 26, 2005, 1:37pm UTC](https://www.ruby-forum.com/t/best-practices-probably-a-newbie-question/48896 "2005-11-26T13:37:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![brucebalmer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@brucebalmer](https://www.ruby-forum.com/u/brucebalmer)\
**Post date:** [November 26, 2005, 1:37pm UTC](https://www.ruby-forum.com/t/best-practices-probably-a-newbie-question/48896/1 "2005-11-26T13:37:24Z")

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Hi:

Can anyone point me to a document of best practices? Here is my  
situation. I can think of 3 solutions, but which is best? There may  
be more solutions I have not considered, so feel free to let me know  
those also.

I have a line like this

@x = model.find(:all, :conditions=\>blah, blah, blah) (which will  
lead to a small number of records, typically less than 100)

I wish to calculate the total of @x.time.

A. I could do that by making another call to the db and asking it to  
give me the total and place that value in a new variable then use  
that variable in my rhtml file. That would keep calculations where  
they belong - off the presentation layer. But it makes another call  
to the db.

B. I could use a for loop and run through the values in @x.time  
totalling them as I go. That would avoid a hit to the db but it  
would involve running through the same array twice, once on the  
controller and once in the rhtml page where I am displaying a table  
row for each element of the array. So this has duplicated effort.

C. I could just do the totalling while using the “for” loop on the  
rhtml page (the one that makes one row of a table for each row from  
the db. This saves a double hit to the db or a double looping  
through the array but seems to clutter up the rhtml file with things  
(calculations) that should not be there.

What “best practice” would experienced rails programmers suggest?

bruce

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**Author:** ![brucebalmer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@brucebalmer](https://www.ruby-forum.com/u/brucebalmer)\
**Post date:** [November 26, 2005, 2:25pm UTC](https://www.ruby-forum.com/t/best-practices-probably-a-newbie-question/48896/2 "2005-11-26T14:25:08Z")

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in controller:

@x = X.find(:all, …)  
@x\_time\_total = @x.inject(0) { |total, x| sum + x.time }

this is the cleanest approach in my opinion.

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<div class="post-metadata">

**Author:** ![brucebalmer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@brucebalmer](https://www.ruby-forum.com/u/brucebalmer)\
**Post date:** [November 27, 2005, 4:35am UTC](https://www.ruby-forum.com/t/best-practices-probably-a-newbie-question/48896/3 "2005-11-27T04:35:59Z")

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Chris:

Thank you.

bruce