Can we create a Foreign Key on the same column which is already created as a Primary Key SQL |Oracle
Can we create FK on the same column which is PK already?
YES
PK + FK both. This can not accept NULL, because it is PK as well. It will not accept duplicates as well, even from FK side there is no as such rule for duplivcate data, but this column is PK as well, so it must follow those characteristics.