Example: Deleting Rows from an ANSI System-Time Table - Analytics Database - Teradata Vantage

ANSI Temporal Table Support

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2023-10-30
dita:mapPath
jqu1628112571823.ditamap
dita:ditavalPath
qkf1628213546010.ditaval
dita:id
esa1472244798285
lifecycle
latest
Product Category
Teradata Vantage™

The following example assumes the DELETE operation is applied to the following system-versioned system-time table named employee_systime:

 eid ename  deptno                        sys_start                          sys_end
---- ------ ------ -------------------------------- --------------------------------
1002 Ash       333 2003-07-01 12:11:00.000000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     222 2004-12-01 00:12:23.120000-08:00 2005-05-01 12:00:00.450000-08:00
1004 Fred      222 2002-07-01 12:00:00.350000-08:00 2005-05-01 12:00:00.350000-08:00
1001 Sania     111 2002-01-01 00:00:00.000000-08:00 9999-12-31 23:59:59.999999+00:00
1003 SRK       111 2004-02-10 00:00:00.000000-08:00 2006-03-01 00:00:00.000000-08:00
1004 Fred      555 2005-05-01 12:00:00.350000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     555 2005-05-01 12:00:00.450000-08:00 9999-12-31 23:59:59.999999+00:00

The closed rows have already been deleted from the table, so are not subject to further deletion. Only the open rows in a system-time table can be deleted. The open rows are returned by a SELECT statement that is not temporally qualified:

SELECT * FROM employee_systime;

 eid ename  deptno                        sys_start                          sys_end
---- ------ ------ -------------------------------- --------------------------------
1002 Ash       333 2003-07-01 12:11:00.000000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     555 2005-05-01 12:00:00.450000-08:00 9999-12-31 23:59:59.999999+00:00
1004 Fred      555 2005-05-01 12:00:00.350000-08:00 9999-12-31 23:59:59.999999+00:00
1001 Sania     111 2002-01-01 00:00:00.000000-08:00 9999-12-31 23:59:59.999999+00:00

DELETE FROM employee_systime WHERE ename=’Sania’;

A simple SELECT shows that the row has been deleted from the table.

SELECT * FROM employee_systime;

Output:

 eid ename  deptno                        sys_start                          sys_end
---- ------ ------ -------------------------------- --------------------------------
1002 Ash       333 2003-07-01 12:11:00.000000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     555 2005-05-01 12:00:00.450000-08:00 9999-12-31 23:59:59.999999+00:00
1004 Fred      555 2005-05-01 12:00:00.350000-08:00 9999-12-31 23:59:59.999999+00:00

A temporal query that shows all open and closed rows in the table reveals that the Sania row has only been logically deleted, but remains inactive in the table as a closed row.

SELECT * 
FROM employee_systime 
FOR SYSTEM_TIME FROM TIMESTAMP'1900-01-01 00:00:00.000001-08:00' TO 
CURRENT_TIMESTAMP;

Output:

 eid ename  deptno                        sys_start                          sys_end
---- ------ ------ -------------------------------- --------------------------------
1002 Ash       333 2003-07-01 12:11:00.000000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     222 2004-12-01 00:12:23.120000-08:00 2005-05-01 12:00:00.450000-08:00
1004 Fred      222 2002-07-01 12:00:00.350000-08:00 2005-05-01 12:00:00.350000-08:00
1001 Sania     111 2002-01-01 00:00:00.000000-08:00 2014-02-22 22:32:01.540000-08:00
1003 SRK       111 2004-02-10 00:00:00.000000-08:00 2006-03-01 00:00:00.000000-08:00
1004 Fred      555 2005-05-01 12:00:00.350000-08:00 9999-12-31 23:59:59.999999+00:00
1005 Alice     555 2005-05-01 12:00:00.450000-08:00 9999-12-31 23:59:59.999999+00:00

In this way, a system-time table maintains a complete history of row deletions in the table.