[RAILS] [Ruby] Big Decimal and DECIMAL

I compared Decimal type columns with numbers but it didn't work as expected

def show
  @item = Item.find(params[:id])
  if @item.price < 1 #price is DECIMAL type
    #Write some processing

When I check the type, it is String. Apparently Decimal is a fixed-point number type and handles more accurate values than floating-point types, so it seems that it will be returned as a character string (naturally ...?)

 -> String


It works as expected when using the BigDecimal library

require 'bigdecimal'

if BigDecimal(@item.price) < 1
    #Write some processing

What are floating point and fixed point in the first place?

Floating-point types such as Float can handle a large number of digits, but errors occur because the numbers after the decimal point cannot be represented by binary numbers. → Rounding error

The fixed-point type solves this problem, but it can handle fewer digits than the floating-point type.


・ Https://docs.ruby-lang.org/ja/latest/library/bigdecimal.html ・ Https://qiita.com/jnchito/items/d0ef71b25732ad5a881c ・ Https://qiita.com/angel_p_57/items/24078ba4aa5881805ab2

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