Trigger on status change - sql

Question

I need to write a trigger in SQL, first of all I show you my table structure
CREATE TABLE ZAMOW
(
IDZAMOW int primary key identity(1,1) not null,
IDKLIENTA int not null REFERENCES KLIENT(IDKLIENTA),
DATA DATE not null DEFAULT(GETDATE()),
STATUS char(1) CHECK(STATUS = 'P' OR STATUS = 'W' OR STATUS = 'Z' OR STATUS = 'A' )DEFAULT('P')
)
CREATE TABLE ZAMOCZESCI
(
IDZAMOW int not null REFERENCES ZAMOW(IDZAMOW),
IDCZESCI int not null REFERENCES CZESC(IDCZESCI),
ILOSC float not null
)
CREATE TABLE CZESC
(
IDCZESCI int primary key identity(1,1) not null,
NAZWA char(30) not null CHECK ((datalength([NAZWA])>(3))),
OPIS char(200) DEFAULT('Brak opisu'),
CENA decimal(10,2) not null
)
CREATE TABLE MAGACZESCI
(
IDMAGAZYNU int not null REFERENCES MAGAZYN(IDMAGAZYNU),
IDCZESCI int not null REFERENCES CZESC(IDCZESCI),
ILOSC float not null
)
I want to create a trigger that will trigger only if ZAMOW.STATUS changes to 'W' or 'Z' and then will subtract all values MAGACZESCI.ILOSC = MAGACZESCI.ILOSC - ZAMOCZESCI.ILOSC identifying id by IDCZESCI
For example if I have in table MAGACZESCI values (1,1,5) and (1,2,5) // 5 pieces of part number 1 and 2, in table ZAMOW(1,1,currentdate,'P'),
and in table ZAMOCZESCI (1,1,3), (1,2,2) 3 pieces of part 1 and 2 pieces of part 2
I want to trigger only if status changes from 'P' -> 'W' OR 'Z'
and then to change values in MAGACZESCI to (1,1,5-3) and (1,2,5-2) identifying by IDCZESCI
This example is for 2 rows but I want it to be more flexible, sometimes even for 100 or more rows
I came up with something like this
CREATE TRIGGER STATUSCHANGE
ON ZAMOW
AFTER UPDATE
AS
IF UPDATE(STATUS)
IF (ZAMOW.STATUS = 'Z' OR ZAMOW.STATUS = 'W')
DECLARE #idczesci int
DECLARE #ilosc float
DECLARE C1 CURSOR FOR SELECT ZAMOCZESCI.IDCZESCI,ZAMOCZESCI.ILOSC FROM ZAMOCZESCI WHERE ZAMOCZESCI.IDZAMOW = ZAMOW.IDZAMOW
OPEN C1
FETCH NEXT FROM C1 INTO #idczesci,#ilosc
WHILE ##FETCH_STATUS = 0
BEGIN
UPDATE MAGACZESCI
SET ILOSC = ILOSC - #ilosc
WHERE IDCZESCI = #idczesci
END
GO
But I don't know how to tell SQL that IF (ZAMOW.STATUS = 'Z' OR ZAMOW.STATUS = 'W') id for rows that are updated, it tells me couldn't bound because of multipart identifier.

Answer 1

This is incomplete as in your attempt you reference the columns that don't exist in the table ZAMOW yet that is what the trigger is on. I suspect that is because we have incomplete DDL as you have keys on tables like MAGAZYN that don't exist in the DDL you provide.
Anyway, this should be enough to get you where you need to be, however, I can't test it, as the columns ILOSC and idczesci don't exist in your sample DDL:
CREATE TRIGGER trg_StatusChange ON dbo.ZAMOW
AFTER UPDATE AS
BEGIN
IF UPDATE ([Status]) BEGIN
UPDATE M
SET ILOSC = ILOSC - i.ILOSC --This column doesn't exist in your table, so where is it coming from?
FROM dbo.MAGACZESCI M
JOIN inserted i ON M.IDCZESCI = i.idczesci --This column doesn't exist in your table, so where is it coming from?
JOIN deleted d ON i.IDZAMOW = d.IDZAMOW --This column doesn't exist in your table, so where is it coming from?
WHERE d.[STATUS] = 'P'
AND i.[status] != 'P';
END;
END;

Answer 2

..just a try...maybe you get something out of it..
drop table if exists ZAMOCZESCI_test
go
drop table if exists MAGACZESCI_test
go
drop table if exists ZAMOW_test
go
drop table if exists CZESC_test
go
CREATE TABLE ZAMOW_test
(
IDZAMOW int primary key identity(1,1) not null,
IDKLIENTA int not null, -- REFERENCES KLIENT(IDKLIENTA),
DATA DATE not null DEFAULT(GETDATE()),
STATUS char(1) CHECK(STATUS = 'P' OR STATUS = 'W' OR STATUS = 'Z' OR STATUS = 'A' )DEFAULT('P')
)
go
insert into ZAMOW_test(IDKLIENTA)
values(510), (520),(530);
go
CREATE TABLE CZESC_test
(
IDCZESCI int primary key identity(1,1) not null,
NAZWA char(30) not null CHECK ((datalength([NAZWA])>(3))),
OPIS char(200) DEFAULT('Brak opisu'),
CENA decimal(10,2) not null
)
go
insert into CZESC_test(NAZWA, CENA)
values('A123', 4), ('B567', 3), ('C009', 7),
--
('X001', 150), ('X002', 500), ('X003', 700)
;
go
CREATE TABLE ZAMOCZESCI_test
(
IDZAMOW int not null REFERENCES ZAMOW_test(IDZAMOW),
IDCZESCI int not null REFERENCES CZESC_test(IDCZESCI),
ILOSC float not null
)
go
insert into ZAMOCZESCI_test(IDZAMOW, IDCZESCI, ILOSC)
values(1, 1, 3), (1, 2, 2), (1, 3, 9),
--2nd&3rd clients
(2, 4, 60), (2, 5, 100), (2, 6, 300),
(3, 5, 150), (3, 6, 120);
go
CREATE TABLE MAGACZESCI_test
(
IDMAGAZYNU int not null,-- REFERENCES MAGAZYN(IDMAGAZYNU),
IDCZESCI int not null REFERENCES CZESC_test(IDCZESCI),
ILOSC float not null
)
go
insert into MAGACZESCI_test(IDMAGAZYNU, IDCZESCI, ILOSC)
values (1001, 1, 5), (1002, 2, 5), (1003, 3, 20),
--
(1004, 4, 200), (1005, 5, 1000), (1006, 6, 2000);
--client 2, assigned 60units of prod4, after trigger: prod4 = 200-60=140
--clients 2&3, assigned 100+150 units of prod5, after trigger: prod5 = 1000 - (100+150) = 750
-- prod6, after trigger: prod6 = 2000 - (300+120) = 1580
go
--based on this
/*
select *
from ZAMOW_test as zam --<--(is replaced by deleted&inserted)
join ZAMOCZESCI_test as zamcze on zam.IDZAMOW = zamcze.IDZAMOW --but this needs to get grouped by IDCZESCI, if multiple "orders" change status in a single update
join MAGACZESCI_test as mag on zamcze.IDCZESCI = mag.IDCZESCI
*/
go
create trigger trgUpdateZAMOW_test on ZAMOW_test for /*after*/ update
as
begin
--set nocount on
--set rowcount 0
--if status did not change from p->w or z, do nothing, return/exit
if not exists
(
select *
from deleted as d
join inserted as i on d.IDZAMOW = i.IDZAMOW
where d.STATUS = 'P'
and i.STATUS in ('W', 'Z')
)
begin
return;
end
--get the "orders" which changed from p->w||z, aggregate their products and subtract the product sums from "inventory"?
update mag
set ILOSC = mag.ILOSC - updcze.sumILOSC --what happens if mag.ILOSC - updcze.sumILOSC < 0 ??
--output deleted.*, inserted.*
from
(
select zamcze.IDCZESCI, isnull(sum(zamcze.ILOSC), 0) as sumILOSC
from deleted as d
join inserted as i on d.IDZAMOW = i.IDZAMOW
join ZAMOCZESCI_test as zamcze on d.IDZAMOW = zamcze.IDZAMOW
where d.STATUS = 'P'
and i.STATUS in ('W', 'Z')
group by zamcze.IDCZESCI
having isnull(sum(zamcze.ILOSC), 0) <> 0
) as updcze
join MAGACZESCI_test as mag on updcze.IDCZESCI = mag.IDCZESCI;
end
go
update ZAMOW_test
set STATUS = 'A' --trigger fires and returns/exits, x->A
go
update ZAMOW_test
set STATUS = 'W' --trigger fires and returns/exits, status:from A->W
go
update ZAMOW_test
set STATUS = 'P' --trigger fires, exits, status:from W->P
go
select 'before', *
from MAGACZESCI_test
update ZAMOW_test
set STATUS = 'W' --trigger fires , and updates mag, status: from P->W
select 'after', *
from MAGACZESCI_test;