CalculateAll
Provides #calculate_all
method on your Active Record models, scopes and relations.
It's a little addition to Active Record's #count
, #maximum
, #minimum
, #average
and #sum
.
It allows to fetch all of the above and any other aggregate functions results in one request, with respect to grouping.
Tested only with Postgres and Mysql only right now. It relies on automatic values type-casting of underlying driver.
Usage
results = YourModel.yourscopes.group(:grouping1).group(:grouping2)
.calculate_all(:column1_max, :column2_distinct_count,
column3_median: 'percentile_cont(0.5) within group (order by column3 desc)')
#calculate_all
tries to mimic magic level of Active Record's #group,
#countand
#pluck`
so result type depends on arguments and on groupings.
Container
If you have no group()
on underlying scope, #calculate_all
will return just one result.
If you have one group, it will return hash of results, with simple keys.
If you have two or more groupings, each result will have an array as a key.
Results
If you provide just one argument to #calculate_all
, its calculated value will be returned as is.
Otherwise results would be returned as hash(es) with symbol keys.
so, Model.calculate_all(:count)
will return just a single integer,
but Model.group(:foo1, :foo2).calculate_all(expr1: 'count(expr1)', expr2: 'count(expr2)')
will return
something like this:
{
['foo1_1', 'foo2_1'] => {expr1: 0, expr2: 1},
['foo1_1', 'foo2_2'] => {expr1: 2, expr2: 3},
...
}
Installation
Add this line to your application's Gemfile:
gem 'calculate-all'
And then execute:
$ bundle
Or install it yourself as:
$ gem install calculate-all
Development
After checking out the repo, run bin/setup
to install dependencies. Then, run rake test
to run the tests. You can also run bin/console
for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install
. To release a new version, update the version number in version.rb
, and then run bundle exec rake release
, which will create a git tag for the version, push git commits and tags, and push the .gem
file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/codesnik/calculate-all.
License
The gem is available as open source under the terms of the MIT License.