part of
https://docs.oracle.com/database/121/SQLRF/statements_7002.htm#SQLRF01402
under INVISIBLE|VISIBLE section (2/5 into the doc)...
Notes on VISIBLE and INVISIBLE Columns
The following notes apply to VISIBLE and INVISIBLE columns:
- An
INVISIBLE column can be used as a partitioning key when specified as part of CREATE TABLE. - You can specify
INVISIBLE columns in a column_expression.
the only place in the syntax where the is a column expression:
virtual_column_definition ::=
in this case I see INVISIBLE|VISIBLE option twice????
Once at the beginning and once at the end of the first line A (column_expression)
so my question is why am I able to specify INVISIBLE|VISIBLE twice here?
Is there something I'm missing.
Lastly a quick example would help if you have the time. if not no worries I am going to be reading several article on INVISIBLE columns