ORACLE trigger instead of insert on view with a nested table - oracle

Question

I have to write a trigger. It compiles everything, but if I want to insert something in my view, i get an error message. Maybe you can help me.
SET DEFINE off;
CREATE OR REPLACE TRIGGER LieferantOV_trig
INSTEAD OF INSERT
ON LIEFERANT_OV
FOR EACH ROW
BEGIN
IF INSERTING THEN
INSERT INTO Lieferant (LiefNr, Name, Adresse)
VALUES(:new.LiefNr, :new.Name, ntTAdresse());
INSERT INTO TABLE (SELECT Adresse FROM Lieferant ) VALUES
(TAdresse(:new.Straße, :new.PLZ, :new.Ort));
END IF;
END;
INSERT INTO Lieferant_OV
VALUES(752443, 'Laepple Teublitz', 'Maxstr. 12', '93158', 'Teublitz');
For the nested Table
CREATE OR REPLACE TYPE TAdresse AS OBJECT(
Straße VARCHAR2(50),
PLZ VARCHAR2(5),
Ort VARCHAR2(50)
);
CREATE TABLE Lieferant(
LiefNr number(6) PRIMARY KEY,
Name varchar2(20) NOT NULL
);
1.
CREATE OR REPLACE TYPE ntTAdresse AS TABLE OF TAdresse;
2.
ALTER TABLE Lieferant ADD Adresse ntTAdresse NESTED TABLE Adresse STORE AS TAdresseNT;
CREATE OR REPLACE VIEW Lieferant_OV (LiefNr, Name, Straße, PLZ, ORT)
AS SELECT k.LiefNr, k.Name, l.Straße, l.PLZ, l.Ort
FROM Lieferant k, table(k.Adresse) l;

Answer 1

The syntax should be like this:
CREATE OR REPLACE TRIGGER LieferantOV_trig
INSTEAD OF INSERT
ON LIEFERANT_OV
FOR EACH ROW
BEGIN
INSERT INTO Lieferant (LiefNr, Name, Adresse)
VALUES(:new.LiefNr, :new.Name, ntTAdresse(TAdresse(:new.Straße,:new.PLZ,:new.ORT));
END;
You can skip IF INSERTING THEN because your trigger fires only on INSERT
Note, by this each record have at maximum only one address, thus a nested table does not make much sense.
In order to add an address to existing Lieferant you can do this one:
CREATE OR REPLACE TRIGGER LieferantOV_trig
INSTEAD OF INSERT
ON LIEFERANT_OV
FOR EACH ROW
DECLARE
lieferantCount INTEGER;
BEGIN
select count(*)
into lieferantCount
from Lieferant
where LiefNr = :new.LiefNr
and Name = :new.Name;
if lieferantCount = 0 then
INSERT INTO Lieferant (LiefNr, Name, Adresse)
VALUES(:new.LiefNr, :new.Name, ntTAdresse(TAdresse(:new.Straße,:new.PLZ,:new.ORT)));
else
UPDATE Lieferant
SET Adresse = Adresse MULTISET UNION ntTAdresse(TAdresse(:new.Straße,:new.PLZ,:new.ORT))
WHERE LiefNr = :new.LiefNr
and Name = :new.Name;
end if;
END;

Answer 2

I think you want do this if you want to keep one row per insertion.
CREATE OR REPLACE TRIGGER LieferantOV_trig
INSTEAD OF INSERT
ON LIEFERANT_OV
FOR EACH ROW
BEGIN
INSERT INTO Lieferant (LiefNr, Name, Adresse)
VALUES(:new.LiefNr, :new.Name, ntTAdresse(TAdresse(:new.Straße, :new.PLZ, :new.Ort)));
END;
/
This works if the Adresse column contain only one Adress. But that is not purpose of a nested table. So you probably want to check if there is an existing row in the table with given LiefNr. If yes, only insert into the nested table.