I tried this with mySQL. Should work with other databases too.
If you have columns named “created_at” or “updated_at” of type datetime in your database table,
Rails will automatically insert the value of now( ), in the column “created_at” when a model corresponding to the table is saved in the database. Similarly it will automatically update the value of the column “updated_at” to the value of now( ), when a model is updated and saved to the database.
“created_on” and “updated_on”, of type date, display the same functionality.
One of the basic Rails philosophy is “Convention over Configuration”, meaning that rails has sensible defaults for a lot of aspects.
If the programmer follows these naming conventions a lot of functionality in the application gets built-in by default.