tsql trigger for copy older data before update - tsql

Question

i need help to create a trigger, i have a database with this table: test01(id, name, id_parent)
CREATE TABLE [dbo].[test01](
[id] [int] IDENTITY(1,1) NOT NULL,
[name] [varchar](64) NOT NULL,
CONSTRAINT [PK_test01] PRIMARY KEY CLUSTERED
(
[id] ASC
)
when an update is executed i need to copy the update row in the same table.
Example data before update
id, name, id_parent
1 , 'bob', null
2 , 'jak', null
if i send:
update test01 set name='newbob' where id=1
i need this result
id, name, id_parent
1 , 'newbob', null <---- updated row
2 , 'jak', null
3 , 'bob', 1 <---- copy of previous row with id_parent referenced to the updated row
i need help to create a trigger for this.
my non working version:
CREATE TRIGGER testtrg
ON test01
INSTEAD OF UPDATE
AS
BEGIN
SET NOCOUNT ON;
insert into test01
select * from inserted
END
GO

Answer 1

it works. you needed to map the id into the id_parent column
drop table test01
CREATE TABLE [dbo].[test01](
[id] [int] IDENTITY(1,1) NOT NULL,
[name] [varchar](64) NOT NULL,
[id_parent][int] NULL,
CONSTRAINT [PK_test01] PRIMARY KEY CLUSTERED
(
[id] ASC
));
insert into test01 (name,id_parent)
values('bob', null),('jak', null)
select * from test01
CREATE TRIGGER testtrg
ON test01
INSTEAD OF UPDATE
AS
BEGIN
SET NOCOUNT ON;
insert into test01(name,id_parent)
select name,id from inserted
END
update test01 set name='bob2' where id=1
select * from test01
output:
id name id_parent
1 bob NULL
2 jak NULL
3 bob2 1