On 19-Jun-2003 Mojtaba Faridzad wrote:
Please don't hi-jack threads.
> Hi,
>
> In a docuement such as Invoice Form, we have a header and a couple of
> records for the detail. In header table, Invoice# can be the PRIMARY KEY
> but
> in detail table, Invoice# is not unique. I think there are two solutions
> to
> choose a Primary Key (in MyISAM type) :
>
> 1) Adding an id field ( auto_increment ) and choose it as PRIMARY KEY
> in this case we have to add another index on Invoice# for making relation
> with the header table
>
> 2) There is another field in detail table with "timestamp" type for
> keeping
> the last change on the record. I want to select ( Invoice# + myTimestamp
> )
> for PRIMARY KEY. in this case I don't need to add a new fields ( id ) and
> another index ( on Invoice# ) to the table.
>
> which one do you prefer and usually use?
Number one (with a composite key).
table invoice_line (
idinv int unsigned not null, // invoice number
line tinyint unsigned auto_increment, // line number
idprod, qty, uom, price, cogs, // product shipped
...
primary key(idinv, line)
)
Regards,
--
Don Read [EMAIL PROTECTED]
-- It's always darkest before the dawn. So if you are going to
steal the neighbor's newspaper, that's the time to do it.
(53kr33t w0rdz: sql table query)
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