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ABC123

jchasko
08-28-2011, 05:40 PM
I'm confused about FK's and Identifying relationships (IRs) in MySQL. I've seen that any FK that is part of a unique ID (not the PK) should be an IR. For instance:

Region
ID
Name

Company
ID
fk_Region_ID

Invoice
ID
fk_Company_ID
fk_Region_ID (Company)

Invoice_Detail
ID
fk_Invoice_ID
fk_Region_ID (Invoice)

For the Invoice_Detail Table:
I assume that fk_Invoice_ID must be identifying?
What about fk_Region_ID?