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Can someone explain a 1:n non identifying relation?
=20
Brian Duke
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Duke, Brian wrote:
>Can someone explain a 1:n non identifying relation?
>
>
>
>Brian Duke
>
>
Yes.
I'm Dan, and I'm unique; there's only one of me.
However if I like a store after an initial purchase from them, I may go
back and another purchase.
1:n
User:Purchase
Dan
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Manageability.
Id(surrogate) can be autoincrement so managed by the engine,
Joins are simpler to write.
Imagine a natural key composed of three or more fields.
Practical, with surrogate you can 'book' a record while not knowing yet all
of the values that compose the natural key.
Just a couple of points.
Claudio
Il giorno 12 set, 2009 12:57 m., "Martin Gainty"
scritto:
what are the advantages to implementing a natural key over surrogate key
?
Martin Gainty
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> Date: Fri, 11 Sep 2009 15:22:57 -0700
> Subject: Re: database design
> From: kykimdba@gmail.com
> To: fuller.artful@gmail.com
> CC: claudio.nanni@gmail.com; andrewhudds@gmail.com; mysql@lists.mysql.com
> > A) You would probably want to populate the Article.Article_Type column =
>
with Article_Type.ID....
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