INSERT INTO View, INSTEAD OF Trigger, Identity, multiple tables? - sql-server

Question

Here as my tables (Entier = Integer // Caractère long variable = Varchar) :
http://i.stack.imgur.com/lNjyy.jpg
I created a view V_Enterprise(idContact, phoneNumber, email, name, city, adress)
I tried to create a Trigger on that View to allow users to update the view :
CREATE TRIGGER test
ON V_Entreprise
INSTEAD OF INSERT
AS
DECLARE #T_ContactId INT
BEGIN
INSERT INTO T_Contact
SELECT i.phoneNumber, i.email
FROM Inserted i
SELECT #T_ContactId = ##IDENTITY
INSERT INTO T_Entreprise
SELECT #T_ContactId, i.name, i.city, i.adress
FROM Inserted i
END ;
As I expected, it work on simple inserts, but when I add couples of rows at once, it fails because #T_ContactId only contains the first id. Can someone help me to fix it ? I feel like I should use INNER JOIN inserts but I can't figure out how to deal with it.

Answer 1

OK you should never set scalar variables to a value in inserted or delted in a trigger.
Use the OUTPUT clause instead to get your id values back.

Answer 2

This trigger uses a loop over a cursor and won't require any particular uniqueness in the tables;
CREATE TRIGGER test
ON V_Enterprise
INSTEAD OF INSERT
AS
BEGIN
DECLARE #name VARCHAR(32)
DECLARE #city VARCHAR(32)
DECLARE #address VARCHAR(32)
DECLARE #pn VARCHAR(32)
DECLARE #email VARCHAR(32)
DECLARE cursor1 CURSOR FOR
SELECT name,city,address,phoneNumber,email FROM inserted;
OPEN cursor1;
FETCH NEXT FROM cursor1 INTO #name, #city, #address, #pn, #email;
WHILE ##FETCH_STATUS = 0
BEGIN
INSERT INTO T_Contact (phoneNumber,email) VALUES (#pn, #email);
INSERT INTO T_Enterprise (idcontact,name,city,address) VALUES
(##IDENTITY,#name,#city,#address);
FETCH NEXT FROM cursor1 INTO #name, #city, #address, #pn, #email;
END
CLOSE cursor1;
DEALLOCATE cursor1;
END
GO

Answer 3

I don't know if this is a good way to do it, but you can do this without relying on unique columns or using a cursor using the OUTPUT clause for INSERT. This approach does make use of an in-memory temporary table that could get big with large inserts.
DECLARE #Table table( NewID BIGINT);
INSERT INTO T_Contact (PhoneNumber)
OUTPUT Inserted.ID
INTO #Table
SELECT PhoneNumber FROM inserted WHERE
;
INSERT INTO T_Enterprise (Contact_ID)
SELECT NewID FROM #Table;

Answer 4

If phoneNumber and email are a unique key in T_Contact then you could do this:
CREATE TRIGGER test
ON V_Entreprise
INSTEAD OF INSERT
AS
DECLARE #T_ContactId INT
BEGIN
INSERT INTO T_Contact
SELECT i.phoneNumber, i.email
FROM Inserted i
SELECT #T_ContactId = ##IDENTITY
INSERT INTO T_Entreprise
SELECT
(SELECT idContact FROM T_Contact
WHERE phoneNumber = i.phoneNumber AND email = i.email),
i.name, i.city, i.adress
FROM Inserted i
END ;