QueryResultPresenter

This is a gem to deal with a variety of query results from the various database adapters that run in ruby. Most of them (pg, mysql2) natively return a query result in the form of an enumerable, with each result being a hash with the column name and row value of the query.

This code adds functionality to the results of these database adapters, and simplifies some common things you need for query reporting, especially online.

This gem uses the decorator pattern, so it adds some additional methods and delegates to the original result for anything it doesn't recognize.

Installation

Add this line to your application's Gemfile:

gem 'query_result_presenter'

And then execute:

$ bundle

Or install it yourself as:

$ gem install query_result_presenter

Usage

All you need to do is call QueryResultPresenter::Presenter.new(result here) on any query result returned as a hash, and you will get these additional methods. If you call an unrecognized method, it will call that method on the original result object using method_missing.

This project started as PgResultPresenter to be used with a postgres database that returnd PgResult objects to which we added functionality. However, since we're open sourcing our BI app, and people will likely use non-postgres db's, this gem is to extend that functionality beyond just postgres.

So, the (result here) that you load into the presenter will be a result from pg, mysql2, or another db connection library. The results can be different types / classes, but most conform to the same format which allows this gem to work.

The format needed for this to work is for results to be returned as hashes, this will not work for query results returned as an array. Most libraries return results as hashes by default, or you are able to change the configuration in the library to return the result as a hash.

The additional functions you get are:

to_html_table turns the query result to an html table

to_csv_data gives you a csv string

to_csv_file(filename) saves a csv file of filename. Will overwrite previous files

headers gets you the headers of the query result (column names)

field_values(column) gets you the values of an individual column as an array

first_result_row gets you the first row of the result

has_results? returns true if there are results

result_count returns the number of results

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request