Temporal tables allow you to “delete” rows for only a portion of their period of validity. The database takes care of adding rows and adjusting valid-time periods to account for the change automatically. The database automatically handles the valid-time modifications for the row, which may involve changing the period bounds and adding new rows to the table.
For example, assume the company grants Fred a year off from his job in 2009. Deleting the Fred row for only that portion of the row period of validity automatically yields two rows for Fred in the table:
DELETE FROM employee_vt FOR PORTION OF job_dur FROM DATE’2009-01-01’ TO DATE’2010-01-01’ WHERE ename=’Fred’; SELECT * FROM employee_vt WHERE ename=’Fred’; eid ename terms job_start job_end ---- ----- ----- ---------- ----------- 1004 Fred PW12 2001/05/01 2009/01/01 1004 Fred PW12 2010/01/01 9999/12/31
Even though this was a DELETE operation, the net effect was to add a row to the table.