This is what I understood (s)he means Scenario: Laptop's price is initially $800...

		rehack on March 27, 2014 \| parent \| context \| favorite \| on: Should "Yes, delete it" be red, or green? This is what I understood (s)he means Scenario: Laptop's price is initially $800 and then increases to $850 before dropping to $825 Design 1: with columns Amount and Kind will just have a single row which will get modified with the latest value Design 2: Will have 3 rows in the above case Difference \| Kind \| Time stamp 800 \| 'Laptop' \| ts 1 +50 \| 'Laptop' \| ts 2 -25 \| 'Laptop' \| ts 3 So this latter design has 'undo' builtin edit: formating

Yes, that's what I've meant. This also gives you easy accountability (rows can have information like user_id, ip, timestamp).