a note about database naming style

docs/guide/db-active-record.md

@@ -96,6 +96,12 @@ $customer->email = 'jane@example.com';
 $customer->save();
 ```
 
+> Note: Obviously, because column names become attribute names of the active record class directly, you
+> get attribute names with underscores if you have that kind of naming schema in your database. For example
+> a column `user_name` will be accessed as `$user->user_name` on the active record object. If you are concerned about code style
+> you should adopt your database naming schema to use camelCase too. However, camelCase if not a requirement, Yii can work
+> well with any other naming style.
+
 
 Connecting to Database
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