Relational properties [Oracle SQL]

column-definition-1,
column-definition-2,
   ...
out-of-line-constraint-1,
out-of-line-constraint-2,
   ...
out-of-line-ref-constraint-1,
out-of-line-ref-constraint-2,
   ...
supplemental-logging-properties

The relational properties clause appears as part in a create table statement for

• heap tables.
• .... to be finished ...

As far as I can see, an out-of-line-ref-constraint is only possible for columns containing a ref to an object.