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Historicization with PostgreSQL improved.

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This commit is contained in:
Michael Hierweck 2019-04-26 10:04:06 +02:00
parent 070f321a06
commit 9c1bed2189
1 changed files with 37 additions and 8 deletions
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43
sql/history-demo.sql
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@ -1,16 +1,16 @@
CREATE FUNCTION historicize() RETURNS trigger
LANGUAGE plpgsql SECURITY DEFINER
AS $$
BEGIN
IF (TG_OP = 'INSERT') OR (TG_OP = 'UPDATE') THEN
EXECUTE format('INSERT INTO ' || TG_TABLE_NAME || '_history VALUES (DEFAULT, now(), txid_current(), False, $1.*)') USING NEW;
EXECUTE format('INSERT INTO %I_history VALUES (DEFAULT, now(), txid_current(), False, $1.*)', TG_TABLE_NAME) USING NEW;
RETURN NEW;
ELSE
EXECUTE format('INSERT INTO ' || TG_TABLE_NAME || '_history VALUES (DEFAULT, now(), txid_current(), True, $1.*)') USING OLD;
EXECUTE format('INSERT INTO %I_history VALUES (DEFAULT, now(), txid_current(), True, $1.*)', TG_TABLE_NAME) USING OLD;
RETURN OLD;
END IF;
END;
$$;
$$
LANGUAGE plpgsql;
CREATE TABLE person (
id serial PRIMARY KEY,
@ -30,6 +30,38 @@ CREATE TABLE person_history (
CREATE TRIGGER person_historicize AFTER INSERT OR DELETE OR UPDATE ON person FOR EACH ROW EXECUTE PROCEDURE historicize();
CREATE OR REPLACE FUNCTION person_history(transaction bigint, VARIADIC groupby text[]) RETURNS TABLE (
history_id integer,
history_timestamp timestamp,
history_transaction bigint,
history_tombstone boolean,
id integer,
name character varying(50),
email character varying(50)
)
AS $$
BEGIN
RETURN QUERY EXECUTE format('SELECT * FROM person_history WHERE history_id IN (SELECT max(history_id) AS history_id FROM person_history WHERE history_transaction <= $1 GROUP BY %s)', array_to_string(groupby, ', ')) USING transaction;
END;
$$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION person_history(VARIADIC groupby text[]) RETURNS TABLE (
history_id integer,
history_timestamp timestamp,
history_transaction bigint,
history_tombstone boolean,
id integer,
name character varying(50),
email character varying(50)
)
AS $$
BEGIN
RETURN QUERY EXECUTE format('SELECT * FROM person_history WHERE history_id IN (SELECT max(history_id) AS history_id FROM person_history GROUP BY %s)', array_to_string(groupby, ', '));
END;
$$
LANGUAGE plpgsql;
INSERT INTO person (name, email) VALUES ('michael', 'michael@hierweck.de');
INSERT INTO person (name, email) VALUES ('annika', 'annika@hierweck.de');
@ -48,6 +80,3 @@ 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);