I’m doing some work for a client which involves extracting some data from a legacy database and displaying it in a web interface. One of the fields in the table is the number of megabytes included in the quota. For some crazy reason this is defined as follows:
CREATE TABLE quota ( bandwidth_in_included DECIMAL(8,2) );
This means that in the web interface I get 10,000.0 MB instead of 10,000 MB. Notice the decimal point. Also I wanted bytes rather than MB since the legacy app was a bit all over the place in this regard.
My first solution was to simple create a virtual attribute in the model to override the type.
class Quota < ActiveRecord::Base # We need it as an int and in bytes def bandwidth_in_included attributes['bandwidth_in_included].to_i * 1000 end end
This worked great except that I’m actually rendering the data to XML to be accessed over a REST service so this was generating XML elements like
Eventually I discovered that you can tell ActiveRecord to override the type, so I ended up with
class Quota < ActiveRecord::Base # We want to treat the bandwidth_included a an integer class << columns_hash['bandwidth_in_included'] def type :integer end end # We need it as an int and in bytes def bandwidth_in_included attributes['bandwidth_in_included].to_i * 1000 end end