Oracle SQL3 3 nesting tables insert problem - sql

Question

I'm making an SQL3 script where I create types and then create tables and nested tables.
The prolem I'm getting happens when I want to insert a row where it says :
ORA-00932: inconsistent datatypes: expected UDT got CHAR
this is an online reproduction of the problem where the types and tables are already created, you can try to insert:
https://www.tutorialspoint.com/oracle_terminal_online.php?fbclid=IwAR0GgaLe2_GvGsEb80eB-D0uKDSDJDr1WNBPiK3mHQqpJQrtfacQ1cf03NA
the following is the types creation script
CREATE TYPE T_Personne ;
/
CREATE TYPE T_SET_Tag AS TABLE OF Varchar2(30);
/
CREATE TYPE T_Message AS OBJECT (
Texte Varchar2(500),
DateEcrit Date,
Tags T_SET_Tag
);
/
CREATE TYPE T_SET_Message AS TABLE OF T_Message;
/
CREATE TYPE T_Contact AS OBJECT(
Per REF T_Personne,
Depuis Date
);
/
CREATE TYPE T_SET_Contact AS TABLE OF T_Contact;
/
CREATE OR REPLACE TYPE T_Personne AS OBJECT (
Prenom Varchar2(30),
Suit T_SET_Contact,
Ecrit T_SET_Message
);
/
this one is the table creation script
CREATE TABLE TAB_Personne OF T_Personne
NESTED TABLE Suit STORE AS TAB_suit,
NESTED TABLE Ecrit STORE AS TAB_ecrit(
NESTED TABLE Tags STORE AS TAB_Tags
);
and finally the script I'm using to insert my new rows
INSERT INTO TAB_Personne VALUES(
'Baam',
T_SET_Contact(),
T_SET_Message()
);
INSERT INTO TAB_Personne VALUES(
'Rachel',
T_SET_Contact(
(SELECT REF(P)
FROM TAB_Personne P
WHERE P.Prenom='Baam'),
to_date('01/01/2018', 'dd/mm/yyyy')
),
T_SET_Message(
'Paris candidat aux jeux Olympiques 2022',
to_date('01/06/2019', 'dd/mm/yyyy'),
T_SET_Tag('JM2022')
)
);
the error message I'm getting is
1 row created.
'Paris candidat aux jeux Olympiques 2022', *
ERROR at line 10:
ORA-00932: inconsistent datatypes: expected UDT got CHAR
I'd be glad if anyone can guide me through this, thanks.

Answer 1

You are specifying a T_SET_Message collection but you then need T_Message objects within that; you're supplying the attributes of that object type, not an actual object of the type. The first element in the (non-)collection is a string, hence the error you get - you've supplied a string ('Paris...') when it's expecting to see a UDT (T_Message('Paris...', ...)).
You are also doing the same thing with the T_SET_Contact collection.
You need to wrap your current attributes in object constructors; so this works:
INSERT INTO TAB_Personne VALUES(
'Rachel',
T_SET_Contact(
T_Contact(
(SELECT REF(P)
FROM TAB_Personne P
WHERE P.Prenom='Baam'),
to_date('01/01/2018', 'dd/mm/yyyy')
)
),
T_SET_Message(
T_Message(
'Paris candidat aux jeux Olympiques 2022',
to_date('01/06/2019', 'dd/mm/yyyy'),
T_SET_Tag('JM2022')
)
)
);
db<>fiddle