fixed_point_field

FixedPointField

Stores floating point values in an integer database column.

Most useful for currency, fixed_point_field is a library that lets you tell your active record classes that some numeric column needs to be upscaled when saved and downscaled when loaded, by some known number of decimal places. It also generates stubs to directly access the fixed point version of the number, if you need to use mathematics and remain exact, you can multiply the fixed width version of your number by another integer and then down convert the result manually. The formula for this is: fixed_num.to_f / (base ** width)

Usage

class Product < ActiveRecord::Base fixed_point_field :price end

prod = Product.new(:price => 12.75) prod.price # => 12.75 prod.price_fixed # => 1275

it is stored as an int

prod.send(:read_attribute, :price) # => 1275

fixed point setter

prod.price_fixed = 1999 prod.price # => 19.99

Other widths and bases

This library was designed to be used to store American currency (USD), but may be useful in other situations as well. To store a number with a fixed point width of 10, use:

fixed_point_field :very_precise_column, :width => 10

You can also store numbers in other bases other than decimal numbers, but any base that is not evenly divisible by 10 will give you rounding errors, negating the value of the plugin. I'm not sure why you'd need this, but here it is:

fixed_point_field :base_twenty_column, :base => 20

Installation

The preferred method of installation is through Rubygems. You can use config.gem, bundler, or manually install the fixed_point_field gem, depending on your version of Rails and desired usage.

Feedback

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