CREATE TABLE structure (a bigint, "b b" date, d text, sys_period tstzrange);
CREATE TABLE structure_history (like structure);
CREATE TRIGGER versioning_trigger
BEFORE INSERT OR UPDATE OR DELETE ON structure
FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'structure_history', false);
-- Insert.
BEGIN;
INSERT INTO structure (a, "b b", d) VALUES (1, '2000-01-01', 'test');
SELECT a, "b b", d FROM structure ORDER BY a, sys_period;
 a |    b b     |  d   
---+------------+------
 1 | 01-01-2000 | test
(1 row)

SELECT * FROM structure_history ORDER BY a, sys_period;
 a | b b | d | sys_period 
---+-----+---+------------
(0 rows)

COMMIT;
-- Make sure that the next transaction's CURRENT_TIMESTAMP is different.
SELECT pg_sleep(0.1);
 pg_sleep 
----------
 
(1 row)

-- Update.
BEGIN;
UPDATE structure SET d = 'blah' WHERE a = 1;
SELECT a, "b b", d FROM structure ORDER BY a, sys_period;
 a |    b b     |  d   
---+------------+------
 1 | 01-01-2000 | blah
(1 row)

SELECT a, "b b", d FROM structure_history ORDER BY a, sys_period;
 a |    b b     |  d   
---+------------+------
 1 | 01-01-2000 | test
(1 row)

COMMIT;
-- Make sure that the next transaction's CURRENT_TIMESTAMP is different.
SELECT pg_sleep(0.1);
 pg_sleep 
----------
 
(1 row)

-- Drop column in the versioned table.
ALTER TABLE structure DROP COLUMN d;
-- Update.
BEGIN;
UPDATE structure SET "b b" = '2001-01-01' WHERE a = 1;
SELECT a, "b b" FROM structure ORDER BY a, sys_period;
 a |    b b     
---+------------
 1 | 01-01-2001
(1 row)

SELECT a, "b b", d FROM structure_history ORDER BY a, sys_period;
 a |    b b     |  d   
---+------------+------
 1 | 01-01-2000 | test
 1 | 01-01-2000 | 
(2 rows)

COMMIT;
-- Make sure that the next transaction's CURRENT_TIMESTAMP is different.
SELECT pg_sleep(0.1);
 pg_sleep 
----------
 
(1 row)

-- Add column to the versioned table.
ALTER TABLE structure ADD COLUMN e text;
-- Update.
BEGIN;
UPDATE structure SET e = 'test' WHERE a = 1;
SELECT a, "b b", e FROM structure ORDER BY a, sys_period;
 a |    b b     |  e   
---+------------+------
 1 | 01-01-2001 | test
(1 row)

SELECT a, "b b", d FROM structure_history ORDER BY a, sys_period;
 a |    b b     |  d   
---+------------+------
 1 | 01-01-2000 | test
 1 | 01-01-2000 | 
 1 | 01-01-2001 | 
(3 rows)

COMMIT;
-- Make sure that the next transaction's CURRENT_TIMESTAMP is different.
SELECT pg_sleep(0.1);
 pg_sleep 
----------
 
(1 row)

-- Add column in the history table.
ALTER TABLE structure_history ADD COLUMN e text;
-- Update.
BEGIN;
UPDATE structure SET e = 'test2' WHERE a = 1;
SELECT a, "b b", e FROM structure ORDER BY a, sys_period;
 a |    b b     |   e   
---+------------+-------
 1 | 01-01-2001 | test2
(1 row)

SELECT a, "b b", d, e FROM structure_history ORDER BY a, sys_period;
 a |    b b     |  d   |  e   
---+------------+------+------
 1 | 01-01-2000 | test | 
 1 | 01-01-2000 |      | 
 1 | 01-01-2001 |      | 
 1 | 01-01-2001 |      | test
(4 rows)

COMMIT;
-- Make sure that the next transaction's CURRENT_TIMESTAMP is different.
SELECT pg_sleep(0.1);
 pg_sleep 
----------
 
(1 row)

-- Drop column in the history table.
ALTER TABLE structure_history DROP COLUMN "b b";
-- Update.
BEGIN;
UPDATE structure SET "b b" = '2012-01-01' WHERE a = 1;
SELECT a, "b b", e FROM structure ORDER BY a, sys_period;
 a |    b b     |   e   
---+------------+-------
 1 | 01-01-2012 | test2
(1 row)

SELECT a, d, e FROM structure_history ORDER BY a, sys_period;
 a |  d   |   e   
---+------+-------
 1 | test | 
 1 |      | 
 1 |      | 
 1 |      | test
 1 |      | test2
(5 rows)

COMMIT;