Re: Does trigger only accept functions?

[veem v]

On Tue, 11 Jun 2024 at 17:03, hubert depesz lubaczewski <dep...@depesz.com>
wrote:

> On Tue, Jun 11, 2024 at 12:47:14AM +0530, veem v wrote:
> > to be called from ~50 triggers? or any other better approach exists to
> > handle this?
>
> pgaudit extension?
>
> Or just write all the changes to single table?
>
> Or use dynamic queries that will build the insert based on the name of
> table the event happened on?
>
> Or pass arguments?
>
> Best regards,
>
> depesz
>
>
Thank you so much. I hope you mean something as below when you say making
it dynamic. Because we have the audit tables having more number of columns
as compared to the source table and for a few the column name is a bit
different.

-- Trigger for deletes
CREATE TRIGGER before_delete
BEFORE DELETE ON source_table
FOR EACH ROW EXECUTE FUNCTION log_deletes();


-- Trigger for source_table1
CREATE TRIGGER before_delete_source_table1
BEFORE DELETE ON source_table1
FOR EACH ROW EXECUTE FUNCTION log_deletes();

-- Trigger for source_table2
CREATE TRIGGER before_delete_source_table2
BEFORE DELETE ON source_table2
FOR EACH ROW EXECUTE FUNCTION log_deletes();


CREATE OR REPLACE FUNCTION log_deletes()
RETURNS TRIGGER AS $$
BEGIN
    IF TG_TABLE_NAME = 'source_table1' THEN
        INSERT INTO delete_audit1 ( col1, col2, col3)
        VALUES (OLD.col1, OLD.col2, OLD.col3);
    ELSIF TG_TABLE_NAME = 'source_table2' THEN
        INSERT INTO delete_audit2 ( col4, col5, col6)
        VALUES (OLD.col4, OLD.col5, OLD.col6);
    -- Add more conditions for other tables
    ELSE
        RAISE EXCEPTION 'Audit table not defined for %', TG_TABLE_NAME;
    END IF;
    RETURN OLD;
END;
$$ LANGUAGE plpgsql;