Example: ALTER TABLE to Convert a Nontemporal Table to an ANSI Bitemporal Table - Advanced SQL Engine - Teradata Database

The following SQL creates a regular nontemporal table, and inserts some rows:

CREATE MULTISET TABLE employee_bitemp (
 eid INTEGER NOT NULL,
 ename VARCHAR(5),
 deptno INTEGER NOT NULL,
 terms VARCHAR(5),
 job_start DATE NOT NULL,
 job_end DATE NOT NULL,
 sys_start TIMESTAMP(6) WITH TIME ZONE NOT NULL,
 sys_end TIMESTAMP(6) WITH TIME ZONE NOT NULL
 )
 PRIMARY INDEX (eid);

INSERT INTO employee_bitemp VALUES 

 (1001,'Sania',111,'TW08',DATE'2002-01-01',DATE'2006-12-31',
  TIMESTAMP'2002-01-01 00:00:00.000000-08:00',
  TIMESTAMP'2002-07-01 12:00:00.350000+00:00');
INSERT INTO employee_bitemp VALUES 
 (1004,'Fred',222,'PW12', DATE'2001-05-01',DATE'9999-12-31',
  TIMESTAMP'2001-05-01 12:00:00.350000-08:00',
  TIMESTAMP'9999-12-31 23:59:59.999999+00:00');
INSERT INTO employee_bitemp VALUES
 (1002,'Ash',333,'TA05',DATE'2003-01-01',DATE'2003-12-31',
  TIMESTAMP'2003-01-01 12:11:00.000000-08:00', 
  TIMESTAMP'9999-12-31 23:59:59.999999+00:00');
INSERT INTO employee_bitemp VALUES 
 (1003,'SRK',111,'TM02',DATE'2004-02-10',DATE'2005-02-10', 
  TIMESTAMP'2004-02-10 00:00:00.000000-08:00', 
  TIMESTAMP'2004-12-01 00:12:23.120000+00:00');
INSERT INTO employee_bitemp VALUES 
 (1005,'Alice',222,'TW10',DATE'2004-12-01',DATE'9999-12-31',
  TIMESTAMP'2004-12-01 12:00:00.450000-08:00', 
  TIMESTAMP'9999-12-31 23:59:59.999999+00:00');
INSERT INTO employee_bitemp VALUES 
 (1010,'Mike',444,'TW07',DATE'2015-01-01',DATE'2016-12-31',
  TIMESTAMP'2004-12-01 00:12:23.120000-08:00', 
  TIMESTAMP'9999-12-31 23:59:59.999999+00:00');

After rows have been inserted, an unqualified SELECT on the table returns all rows:

SELECT * FROM employee_bitemp;

 eid ename deptno terms   job_start     job_end                         sys_start                           sys_end
---- ----- ------ -----  ----------  ----------  --------------------------------  --------------------------------
1002 Ash      333  TA05  2003/01/01  2003/12/31  2003-01-01 12:11:00.000000-08:00  9999-12-31 23:59:59.999999+00:00
1005 Alice    222  TW10  2004/12/01  9999/12/31  2004-12-01 12:00:00.450000-08:00  9999-12-31 23:59:59.999999+00:00
1010 Mike     444  TW07  2015/01/01  2016/12/31  2004-12-01 00:12:23.120000-08:00  9999-12-31 23:59:59.999999+00:00
1001 Sania    111  TW08  2002/01/01  2006/12/31  2002-01-01 00:00:00.000000-08:00  2002-07-01 12:00:00.350000+00:00
1004 Fred     222  PW12  2001/05/01  9999/12/31  2001-05-01 12:00:00.350000-08:00  9999-12-31 23:59:59.999999+00:00
1003 SRK      111  TM02  2004/02/10  2005/02/10  2004-02-10 00:00:00.000000-08:00  2004-12-01 00:12:23.120000+00:00

The following ALTER TABLE statement adds valid time to the table:

ALTER TABLE employee_bitemp
 ADD PERIOD FOR job_dur(job_start,job_end) AS VALIDTIME;

A simple select from the table still returns all rows, as it would from any valid-time table:

SELECT * FROM employee_bitemp;

 eid ename deptno terms   job_start     job_end                         sys_start                           sys_end
---- ----- ------ -----  ----------  ----------  --------------------------------  --------------------------------
1002 Ash      333  TA05  2003/01/01  2003/12/31  2003-01-01 12:11:00.000000-08:00  9999-12-31 23:59:59.999999+00:00
1005 Alice    222  TW10  2004/12/01  9999/12/31  2004-12-01 12:00:00.450000-08:00  9999-12-31 23:59:59.999999+00:00
1010 Mike     444  TW07  2015/01/01  2016/12/31  2004-12-01 00:12:23.120000-08:00  9999-12-31 23:59:59.999999+00:00
1001 Sania    111  TW08  2002/01/01  2006/12/31  2002-01-01 00:00:00.000000-08:00  2002-07-01 12:00:00.350000+00:00
1004 Fred     222  PW12  2001/05/01  9999/12/31  2001-05-01 12:00:00.350000-08:00  9999-12-31 23:59:59.999999+00:00
1003 SRK      111  TM02  2004/02/10  2005/02/10  2004-02-10 00:00:00.000000-08:00  2004-12-01 00:12:23.120000+00:00

The following ALTER TABLE statements add system time to the table:

ALTER TABLE employee_bitemp
 ADD PERIOD FOR SYSTEM_TIME(sys_start,sys_end)
 ADD sys_start TIMESTAMP(6) WITH TIME ZONE NOT NULL
               GENERATED ALWAYS AS ROW START
 ADD sys_end TIMESTAMP(6) WITH TIME ZONE NOT NULL
               GENERATED ALWAYS AS ROW END;
ALTER TABLE employee_bitemp
 ADD SYSTEM VERSIONING;

Because the table now includes a system-time dimension, rows that had dates for sys_end that were not 9999-12-31 23:59:59.999999+0:0 are considered closed rows, logically deleted from the database, so now a simple select shows only four rows:

SELECT * FROM employee_bitemp;

 eid ename deptno terms   job_start     job_end                         sys_start                           sys_end
---- ----- ------ -----  ----------  ----------  --------------------------------  --------------------------------
1002 Ash      333  TA05  2003/01/01  2003/12/31  2003-01-01 12:11:00.000000-08:00  9999-12-31 23:59:59.999999+00:00
1005 Alice    222  TW10  2004/12/01  9999/12/31  2004-12-01 12:00:00.450000-08:00  9999-12-31 23:59:59.999999+00:00
1010 Mike     444  TW07  2015/01/01  2016/12/31  2004-12-01 00:12:23.120000-08:00  9999-12-31 23:59:59.999999+00:00
1004 Fred     222  PW12  2001/05/01  9999/12/31  2001-05-01 12:00:00.350000-08:00  9999-12-31 23:59:59.999999+00:00