Как хранить JSON новые данные внутри триггера в PostgreSQL?

Question

я пытаюсь сделать, как описано в:

https://wiki.postgresql.org/wiki/Audit_trigger

Auditing values as JSON

For PostgreSQL 9.2, or 9.1 with the fantastic json_91 addon, you can log the old and new values in the table as structured json instead of flat text, giving you much more power to query your audit history. Just change the types of v_old_data, v_new_data, original_data and new_data from TEXT to json, then replace ROW(OLD.) and ROW(NEW.) with row_to_json(OLD) and row_to_json(NEW) respectively.

Однако это получить мне ошибку:

CREATE OR REPLACE FUNCTION add_log (name text, Action TEXT, data jsonb, OUT RETURNS BOOLEAN) 
AS $$ 
BEGIN 
    RETURNS = true; 
END; 
$$ 
LANGUAGE 'plpgsql'; 

CREATE OR REPLACE FUNCTION log_city() RETURNS TRIGGER AS 
$$ 
DECLARE 
v_new_data jsonb; 
BEGIN 
    IF (TG_OP = 'UPDATE') THEN 
     RETURN NEW; 
    ELSIF (TG_OP = 'INSERT') THEN 
     v_new_data := row_to_jsonb(NEW); 
     EXECUTE add_log('City', 'City.New', v_new_data); 
     RETURN NEW; 
    END IF; 
    RETURN NULL; -- result is ignored since this is an AFTER trigger 
END; 
$$ LANGUAGE plpgsql; 

INSERT INTO Location (city, state, country) values ('a', 'b' , 'c') 

Это сказать:

ERROR: function row_to_jsonb(location) does not exist

Если я ставлю v_new_data := row_to_jsonb(ROW(NEW)); то я получаю:

ERROR: function row_to_jsonb(record) does not exist

Answer 1

Об этом говорится в documentation, что

Table 9-42 shows the functions that are available for creating json and jsonb values. (There are no equivalent functions for jsonb, of the row_to_json and array_to_json functions. However, the to_jsonb function supplies much the same functionality as these functions would.)

, таким образом, это row_to_json, который должен быть использован. row_to_jsonb не существует, но row_to_json дает желаемый результат для типа JSONB.