Hello. I have three tables. Preferences, Clients, and clientPreferences. The relation is many-to-many.

Preferences {
  id
  ...
}

Clients {
  id
  ...
}

clientPreferences {
  id
  clientId
  preferenceId
}

Now, a preference can be attached/detached to multiple clients. My question is how will I update existing record in

clientPreferences

and at the same time, add a record if it doesn’t exist? My HTTP endpoint for this is

PATCH /preferences/:id

with the JSON request body of

{
  "clientIds": [
    1,
    2,
    3
  ]
}