Track changes when updating a record

How do I check if the data is changed when I edit a record?

So before update

game.player=1

after update / edit

game.player=2

for example

how to track changes (check if changed) and do something in ruby on rails, when the data is changed.

Have a look at ActiveModel::Dirty

You can check if a model has been changed by doing:

game.changed?

Or an individual field like:

game.player_changed?

Both return a boolean value.

All changes are also kept in a hash. This comes in handy if you want to use the values.

game.changes #=> {:player => [1,2]}