I do not know how to create log trigger - oracle

Question

I need to create log trigger for after update, after insert and before delete.
In the accounts_history table I have more rows than in the table of accounts and it confuses me
How to write that trigger?
I tried to do it but I did not succeed, This is how I created tables and sequences.
I'm a beginner in Oracle and plsql
I'm sorry if I did not explain my problem well.
create table accounts (
id number,
name varchar2(32),
amount number,
date date
);
create sequnce acc_seq_id
start wtih 1
increment by 1
nocache
nocycle;
create table accounts_history (
id number
, old_name varchar2(32)
, new_name varchar2(32)
, old_amount number
, new_amount number
, change_date date
);
My trigger for only after update
create or replace trigger after_update
after update
on accounts referencing new as new old as old
for each row
begin
iNSERT INTO account_history
(
id,
name,
old_name,
amount,
old_amount,
date
)
values
(
:old.id,
:new.name,
:old.old_name,
:new.amount,
:old.old_amount,
sysdate
);
end;
/
The error:
SQL> show error
Errors for TRIGGER AFTER_UPDATE:
LINE/COL ERROR
-------- --------------------------------------------------------------
2/1 PL/SQL: SQL Statement ignored
9/2 PL/SQL: ORA-01747: invalid user.table.column, table.column, or
column specification
13/2 PLS-00049: bad bind variable 'OLD.ID'
14/2 PLS-00049: bad bind variable 'NEW.NAME'
15/2 PLS-00049: bad bind variable 'OLD.OLD_NAME'
16/2 PLS-00049: bad bind variable 'NEW.AMOUNT'
17/2 PLS-00049: bad bind variable 'OLD.OLD_AMOUNT'
SQL>

Answer 1

The values you insert come from the ACCOUNTS table, the columns you target come ACCOUNT_HISTORY table. You have mixed them up, which is why you get the ORA-01747 error. Try this:
create or replace trigger after_update
after update on accounts
referencing new as new old as old
for each row
begin
INSERT INTO account_history
(
id,
new_name,
old_name,
new_amount,
old_amount,
change_date
)
values
(
:old.id,
:new.name,
:old.name,
:new.amount,
:old.amount,
sysdate
);
End;
/