Hi (not sure if the Subject: field is correct, but here goes ..),
I'm trying to build some more complexity into the db that I mentioned
recently. If in the 'clients' table, I have
client_id int NOT NULL PRIMARY KEY CHECK (client_id > 0)
name varchar(50) NOT NULL
[...]
... and in the 'sales' table, I have ...
sale_id int NOT NULL PRIMARY KEY CHECK (sale_id > 0)
sold_to INT NOT NULL REFERENCES clients (client_id)
[...]
So when a sale is entered, postgreSQL keeps a record of who it was sold
to. Now what happens if I want to delete the client who bought the
item in question ? I'm going to have a 'sales' table that references a
buyer who no longer exists (in db terms, naturally). I wondered aloud
(talking to the wall, sort of) if I could reference clients.client_id
to sales.sale_id, but wouldn't that stop my adding a client who hasn't
yet made a purchase ?
Thanks in advance.
D.
