as mentioned earlier, i am from Oracle environment, just want to clear the confusion, please guide and confirm this:

what I understand that these are like Primary Key and Foreign Key relationship? 

One2Many is Primary Key of a Model (Table) and Many2One is Foreign Key in another Model to create this relationship, for example:

Department ID of table Departments is One2Many (Primary Key) 

Department ID of table Employees is Many2One (Foreign Key)

please correct me if I am wrong.

regards