The extension allows storing the history of data changes.
Download the files from dist to your extension folder PostgreSQL and run the following commands.
Create a new schema for convenience.
CREATE SCHEMA "history";
ALTER ROLE "postgres" SET search_path TO "public", "history";
Install the extension.
CREATE EXTENSION "pg_history"
SCHEMA "history"
VERSION '1.0';
More about the extension and the control file
| # | primary_key | dml | data | timestamp |
|---|---|---|---|---|
| 1 | INSERT | {"id": 4, "nickname": "Max", "password": null} | 2022-08-06 12:18:02.613552 | |
| 2 | {"id": 4} | UPDATE | {"nickname": "Max N"} | 2022-08-06 12:18:13.486149 |
| 3 | {"id": 4} | UPDATE | {"nickname": "Max NM", "password": null} | 2022-08-06 12:18:20.433618 |
| 4 | {"id": 4} | DELETE | 2022-08-06 12:18:22.118845 |
To store data changes, you need to add a trigger_history() trigger from the extension to the table.
CREATE TRIGGER history
AFTER INSERT OR UPDATE OR DELETE
ON users
FOR EACH ROW
EXECUTE PROCEDURE trigger_history('history');
-- OR
CREATE TRIGGER history
AFTER INSERT OR UPDATE OR DELETE
ON users
FOR EACH ROW
EXECUTE PROCEDURE trigger_history('history', '{ password }');
-- OR
CREATE TRIGGER history
AFTER INSERT OR UPDATE OR DELETE
ON users
FOR EACH ROW
EXECUTE PROCEDURE trigger_history('history', '{ password }', '{ created_at, updated_at }');
Function trigger_history("history_schema" TEXT[, "hidden_columns" TEXT[] = NULL][, "unsaved_columns" TEXT = NULL]), where:
"history_schema"a schema where a table will be created to store the history of changes, inherited from the"history"table;"hidden_columns"array of columns that values cannot be saved;"unsaved_columns"array of columns that cannot be saved.
helpers/*.sqlhelper functions- types/DML.sql Data Manipulation Language
- tables/history.sql parent table for change history
triggers/*.sql- test/*.sql test files