From 143fbbddbbce84f44434c58828e2a537553e69ea Mon Sep 17 00:00:00 2001
From: "Hongli Lai (Phusion)" <hongli@phusion.nl>
Date: Sat, 13 Sep 2008 12:54:45 +0200
Subject: Clarify decimal precision and scale options.

---
 .../connection_adapters/abstract/schema_definitions.rb              | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index b764f26ec8..bcb975e8e1 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -341,6 +341,12 @@ module ActiveRecord
       # * <tt>:scale</tt> -
       #   Specifies the scale for a <tt>:decimal</tt> column.
       #
+      # For clarity's sake: the precision is the number of significant digits,
+      # while the scale is the number of digits that can be stored following
+      # the decimal point. For example, the number 123.45 has a precision of 5
+      # and a scale of 2. A decimal with a precision of 5 and a scale of 2 can
+      # range from -999.99 to 999.99.
+      #
       # Please be aware of different RDBMS implementations behavior with
       # <tt>:decimal</tt> columns:
       # * The SQL standard says the default scale should be 0, <tt>:scale</tt> <=
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