===== In Database Archiving =====
==== Enabling ====
Can be enabled with CREATE or ALTER TABLE commands ...
<code>CREATE TABLE employees (
  id          NUMBER,
  description VARCHAR2(20)
) ROW ARCHIVAL;

ALTER TABLE employees ROW ARCHIVAL;</code>

This will create a hidden column called ORA_ARCHIVE_STATE.\\
By default this column will have a value of 0 for each row.\\
Any value greater than zero makes a SELECT statement ignore this row when ROW ARCHIVAL VISIBILITY is set to ACTIVE.\\

==== Disabling ====
<code>ALTER TABLE employees NO ROW ARCHIVAL;</code>

==== Displaying Archived Rows ====
<code>-- Make archived rows visible.
ALTER SESSION SET ROW ARCHIVAL VISIBILITY = ALL;

-- Make archived rows invisible again.
ALTER SESSION SET ROW ARCHIVAL VISIBILITY = ACTIVE;</code>