Equivalente Oracle DB di aggiornamento chiave duplicata

Dovresti usare un MERGE . Qualcosa come

MERGE INTO users dest
  USING( SELECT 1 user_id, 10 points FROM dual) src
     ON( dest.user_id = src.user_id )
 WHEN MATCHED THEN
   UPDATE SET points = src.points
 WHEN NOT MATCHED THEN
   INSERT( user_id, points ) 
     VALUES( src.user_id, src.points );