Oracle 21c

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CREATE TABLE faktura ( 
  extnr        VARCHAR2(32), 
  fakturanr    NUMBER,
  fakturadate  DATE, 
  partner_name VARCHAR2(32)
);
CREATE OR REPLACE VIEW view_faktura AS 
SELECT extnr, fakturanr, fakturadate 
  FROM faktura;
CREATE TABLE log_table( 
  id             NUMBER GENERATED BY DEFAULT AS IDENTITY, 
  field_changed  VARCHAR2(30), 
  old_value      VARCHAR2(32), 
  new_value      VARCHAR2(32), 
  fakturanr      NUMBER,
  date_of_change DATE
);
create or replace trigger ChangeOnFaktura
  after update on faktura
  for each row
BEGIN
  IF :OLD.extnr <> :NEW.extnr
  OR (:OLD.extnr IS NULL AND :NEW.extnr IS NOT NULL)
  OR (:OLD.extnr IS NOT NULL AND :NEW.extnr IS NULL)
  THEN
    insert into log_table (
      old_value,
      new_value,
      date_of_change,
      field_changed,
      fakturanr
    ) values (
      :OLD.extnr,
      :NEW.extnr,
      SYSDATE,
      'EXTNR',
      :NEW.fakturanr
    );
  END IF;
  
  IF :OLD.partner_name <> :NEW.partner_name
  OR (:OLD.partner_name IS NULL AND :NEW.partner_name IS NOT NULL)
  OR (:OLD.partner_name IS NOT NULL AND :NEW.partner_name IS NULL)
  THEN
    insert into log_table (
      old_value,
      new_value,
      date_of_change,
      field_changed,
      fakturanr
    ) values (
      :OLD.partner_name,
      :NEW.partner_name,
      SYSDATE,
      'PARTNER_NAME',
      :NEW.fakturanr
    );
  END IF;
END;
/
SELECT * FROM USER_ERRORS;
INSERT INTO faktura(extnr, fakturanr, fakturadate, partner_name)
VALUES('1234/12', 1, DATE '2022-01-01', 'Global Sellers LTD');
1 rows affected

INSERT INTO faktura(extnr, fakturanr, fakturadate, partner_name)
VALUES('111', 2, DATE '2022-01-02', 'Thomas Limited');
1 rows affected

UPDATE view_faktura 
   SET extnr = '21' 
 WHERE fakturanr = 2
1 rows affected

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
SELECT * FROM log_table;


ID
FIELD_CHANGED
OLD_VALUE
NEW_VALUE
FAKTURANR
DATE_OF_CHANGE


1
EXTNR
111
21
2
2023-07-27 12:54:00


UPDATE faktura 
   SET extnr = '123',
       partner_name = 'ABC'
 WHERE fakturanr = 1
1 rows affected

SELECT * FROM log_table;


ID
FIELD_CHANGED
OLD_VALUE
NEW_VALUE
FAKTURANR
DATE_OF_CHANGE


1
EXTNR
111
21
2
2023-07-27 12:54:00

2
EXTNR
1234/12
123
1
2023-07-27 12:54:00

3
PARTNER_NAME
Global Sellers LTD
ABC
1
2023-07-27 12:54:00


UPDATE faktura 
   SET extnr = '123',
       partner_name = 'DEF'
 WHERE fakturanr = 1
1 rows affected

SELECT * FROM log_table;


ID
FIELD_CHANGED
OLD_VALUE
NEW_VALUE
FAKTURANR
DATE_OF_CHANGE


1
EXTNR
111
21
2
2023-07-27 12:54:00

2
EXTNR
1234/12
123
1
2023-07-27 12:54:00

3
PARTNER_NAME
Global Sellers LTD
ABC
1
2023-07-27 12:54:00

4
PARTNER_NAME
ABC
DEF
1
2023-07-27 12:54:00
ID	FIELD_CHANGED	OLD_VALUE	NEW_VALUE	FAKTURANR	DATE_OF_CHANGE
1	EXTNR	111	21	2	2023-07-27 12:54:00
2	EXTNR	1234/12	123	1	2023-07-27 12:54:00
3	PARTNER_NAME	Global Sellers LTD	ABC	1	2023-07-27 12:54:00