> if the user change the currency_id in the customer record then i have

to change all the currency_id in sales order which reference to this
customer

Cascading update on the foreign key.

> i have to prevent the user from changing the currency id ones its been

used in sales order

Before update trigger on the sales order which will prevent updates once
the sales order has been processed. You can either ignore the update
and log the fact, or throw exception. If the latter, the cascading
update may not work.

-----Original Message-----
From: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] On Behalf Of reynaldi81
Sent: Tuesday, April 10, 2007 10:42 AM
To: firebird-support@yahoogroups.com
Subject: [firebird-support] Re: get foreign key

> So, many companies do not actually delete a customer's record like

that.

> Instead, they have a flag in the record that specifies whether the
> customer is an "active" customer or not. When the user tries to

"delete"

> a customer, the software simply marks the customer "inactive" or
> "deleted", which causes their information to not show up on active
> customer lists, etc., but doesn't actually delete any information

from the

> database.

You're right. Deleting a record is a bad idea. however, i do need to
know whether the current customer record have active foreign key
references. consider this case. i have "currency_id" field in customer
table. this currency_id will be used in each sales order. if the user
change the currency_id in the customer record then i have to change all
the currency_id in sales order which reference to this customer.
so, i have to prevent the user from changing the currency id ones its
been used in sales order.

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