On Tue, Mar 16, 2010 at 10:06 AM, Aaron Cooper <[email protected]> wrote:
> An example of what has caused my concern here is a table called "Devices" > which will store information on individual physical electronic devices. He > has made the primary keys DeviceID, CustomerID, CountryID and DeviceTypeID. > > This seems to be a massive overkill even in my limited DB design experience. > Each device will appear only once in this table, so why is the DeviceID not > good enough alone? For the primary key I agree with you, a unique identifier for the device should suffice (note I'm not addressing the natural vs surrogae issue). The customerID, countryID and DeviceTypeID, these are presumably foriegn keys held in the table. They need to be indexed to make ensuring referential integrity cheaper to maintain, but (except in very unusual circumstances) I find it hard to see why they need to be in a primary key. Just my 10c worth. -- Bruce Clement Home: http://www.clement.co.nz/ Twitter: http://twitter.com/Bruce_Clement Google Buzz: http://www.google.com/profiles/aotearoanz "Before attempting to create something new, it is vital to have a good appreciation of everything that already exists in this field." Mikhail Kalashnikov -- NZ PHP Users Group: http://groups.google.com/group/nzphpug To post, send email to [email protected] To unsubscribe, send email to [email protected]
