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create table products (
productid int identity primary key,
name varchar(255)
)
create table orders (
orderid int identity primary key,
x int
)
create table reminders (
ReminderId int identity primary key,
parentId int, -- presumably
type varchar(255),
check (type in ('product', 'order')),
parent_productid as (case when type = 'product' then parentId end) persisted,
parent_orderid as (case when type = 'order' then parentId end) persisted,
foreign key (parent_productid) references products(productId),
foreign key (parent_orderid) references orders(orderid)
);
insert into products (name) values ('test')
1 rows affected
insert into orders (x) values (-1)
1 rows affected
insert into orders (x) values (-2)
1 rows affected
-- should work
insert into reminders (parentId, type) values (1, 'product')
1 rows affected
-- should work
insert into reminders (parentId, type) values (2, 'order')
1 rows affected
-- should fail
insert into reminders (parentId, type) values (3, 'product')
Msg 547 Level 16 State 0 Line 2
The INSERT statement conflicted with the FOREIGN KEY constraint "FK__reminders__paren__29572725". The conflict occurred in database "fiddle_7add1d814d904328b7eded90122f0b6b", table "dbo.products", column 'productid'.
Msg 3621 Level 0 State 0 Line 2
The statement has been terminated.