FusionCharts Ruby on Rails Wrapper can be downloaded from here.

In addition to directly specifying the chart data (or the URL for the file in which the chart data is stored) directly in the JSON/XML code, you can also fetch data for the chart from a database.

This section showcases how you can do this using the FusionCharts Ruby on Rails wrapper.

As an example, in this section, you will be shown how you can create a drill-down chart by fetching the required data from a database.

Before you proceed, make sure you have installed and set up the plugin correctly.

Creating a Drill-down Chart

Assume that you have a fusioncharts_sample database that stores the population of all countries in the world, in the Country table, and the population of all cities in each country, in the City table.

Using this data, you want to plot a column 2D chart showing the top 10 most populous countries in the world. Furthermore, you want to render this column 2D chart as a drill-down chart, where clicking each data plot shows another chart plotting the top 10 populous cities of that country.

You can download this database from the MYSQL website or refer to the sample database available here.

The column 2D chart, with the drill-down functionality, that we need to render here looks like this:

The data structure needed to create the above chart goes into the app/controllers/examples_controller.rb file. It is as given below:

# Example to demonstrate the creation of a drill - down chart by fetching data from a database.
# The `country`
action is defined to load the base column 2D chart— the one that shows the top# 10 populous countries and has clickable data plots.
# It fetches the country list from the * * Country * * table and then prepares the data in
# a format compatible with FusionCharts.
def country
# The `select`
query is used to retrieve the name, population, and country code of the 10
# countries having the highest population, in descending order.
countries = Country.select(: name, : population, : code).order(population: : desc).limit(10)
top_ten_populous_countries = []
# Iterate through the list of countries in the database and create an array of hashes that
# stores the label
for each country data plot and its population value.
#The hash also stores the drill - down link
for the city chart corresponding to each country
# data plot.
countries.each do |
country |
top_ten_populous_countries.push({
    : label => country.name,
    : value => country.population,
    : link => "#{example_drilldown_path}/#{country.code}"
})
end
# Create a new FusionCharts instance that initializes the chart height, width, type, container div
# id, data source, and the data format
@ chart = Fusioncharts::Chart.new({
    : height => 400,
    : width => 600,
    : type => 'column2d',
    : renderAt => 'chart-container',
    # Chart data is passed to the `dataSource`
    parameter,
    as hashes,
    in the form of
    # key - value pairs.
    : dataSource => {
        : chart => {
            : caption => 'Top 10 Most Populous Countries',
            : xAxisname => 'Quarter',
            : yAxisName => 'Amount ($)',
            : numberPrefix => '$',
            : theme => 'fint',
        },
        # The data in the array of hashes is now stored in the `top_ten_populous_countries`
        # variable in the FusionCharts consumable format.
        : data => top_ten_populous_countries
    }
})
end
# The `drilldown` action is defined to load the chart with the drill - down functionality.
# It fetches the list of cities from the * * City * * table, based on the country selected in the
# base chart.
# It then prepares the data in a format compatible with FusionCharts.
def drilldown
# The `select` query is used to retrieve the name and population of the top ten cities
# based on the country code for the selected country, in descending order.
cities = City.select(: name, : population).where(: countrycode, params[: id]).order(population: : desc).limit(10)
top_ten_populous_cities = []
# Iterate through the list of cities in the database and create an array of hashes that
# stores the label
for each city data plot and the its population value.
cities.each do |
city |
top_ten_populous_cities.push({
    : label => city.name,
    : value => city.population
})
end
# Create the FusionCharts object in the controller action.
@chart = Fusioncharts::Chart.new({
    : height => 400,
    : width => 600,
    : type => 'column2d',
    : renderAt => 'chart-container',
    : dataSource => {
        : chart => {
            : caption => 'Top 10 Most Populous City in selected Country',
            : xAxisname => 'Quarter',
            : yAxisName => 'Amount ($)',
            : numberPrefix => '$',
            : theme => 'fint',
        },
        : data => top_ten_populous_cities
    }
})
end

There! You have now seen how you can fetch data from a database to render charts, using the FusionCharts Ruby on Rails wrapper.