Odoo 12 Development Essentials - Fourth Edition

Methods for singleton records – @api.one

In some cases, the method is prepared to work with a single record (a singleton). Here, we could use the  @api.one decorator that's still available, but announced as deprecated since Odoo 9. It wraps the decorated method, doing the for loop iteration, calling the decorated method with it one record at a time, and then returning a list with the results. So, inside an @api.one decorated method, self is guaranteed to be a singleton. 

The return value of @api.one can be tricky; it returns a list, not the data structure returned by the actual method. For example, if the method code returns dict, the actual return value is a list of dict values. This misleading behavior was the main reason the method was ...