I'm not sure if this can be called a polymorphic association - what is needed is to for each
Message to have a
Sender Contact and a
Sender Contact and
Recipient Contact could be one of 2+ types. Currently SMS and Email are supported but more may come.
I have this urge to eliminate a possible duplication that would appear in case of having two different tables -
type column is a kinda of a DB-modeling smell.
But I'm not a DB modelling expert and rather looking for an advise from an experts how to properly model those relationships.
Any input is appreciated.