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Historicization with PostgreSQL.

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Michael Hierweck 2019-04-25 17:17:03 +02:00
parent 7c7d79c870
commit da00c80b34
1 changed files with 53 additions and 0 deletions
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sql/history-demo.sql Normal file
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CREATE FUNCTION historicize() RETURNS trigger
LANGUAGE plpgsql SECURITY DEFINER
AS $$
BEGIN
IF (TG_OP = 'INSERT') OR (TG_OP = 'UPDATE') THEN
EXECUTE format('INSERT INTO ' || TG_TABLE_NAME || '_history VALUES (DEFAULT, now(), txid_current(), False, $1.*)') USING NEW;
RETURN NEW;
ELSE
EXECUTE format('INSERT INTO ' || TG_TABLE_NAME || '_history VALUES (DEFAULT, now(), txid_current(), True, $1.*)') USING OLD;
RETURN OLD;
END IF;
END;
$$;
CREATE TABLE person (
id serial PRIMARY KEY,
name character varying(50) NOT NULL UNIQUE,
email character varying(50) NOT NULL UNIQUE
);
CREATE TABLE person_history (
history_id serial PRIMARY KEY,
history_timestamp timestamp NOT NULL,
history_transaction bigint NOT NULL,
history_tombstone boolean NOT NULL,
id integer NOT NULL,
name character varying(50) NOT NULL,
email character varying(50) NOT NULL
);
CREATE TRIGGER person_historicize AFTER INSERT OR DELETE OR UPDATE ON person FOR EACH ROW EXECUTE PROCEDURE historicize();
INSERT INTO person (name, email) VALUES ('michael', 'michael@hierweck.de');
INSERT INTO person (name, email) VALUES ('annika', 'annika@hierweck.de');
UPDATE person SET email='mh@hierweck.de' WHERE name='michael';
UPDATE person SET email='ah@hierweck.de' WHERE name='annika';
DELETE FROM person WHERE name='michael';
DELETE FROM person WHERE name='annika';
INSERT INTO person (name, email) VALUES ('michael', 'michael@hierweck.de');
INSERT INTO person (name, email) VALUES ('annika', 'annika@hierweck.de');
BEGIN;
INSERT INTO person (name, email) VALUES ('mx', 'mx@hierweck.de');
INSERT INTO person (name, email) VALUES ('ax', 'ax@hierweck.de');
UPDATE person SET email='mxx@hierweck.de' WHERE name='mx';
UPDATE person SET email='axx@hierweck.de' WHERE name='ax';
COMMIT;
SELECT * FROM person_history WHERE history_id IN (SELECT max(history_id) AS history_id FROM person_history WHERE history_transaction <= 12345 GROUP BY id);
SELECT * FROM person_history WHERE history_id IN (SELECT max(history_id) AS history_id FROM person_history WHERE history_transaction <= 12345 GROUP BY name);