roger.plowman (3/3/2010)

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From an implementation standpoint, using SQL Server, their rigourous approach will produce sub-optimal results. Page fragmentation being the most glaring, along with the performance hit of having to constantly...

The article by Codd that I quoted was talking about normalization of FDs and MVDs generally, not specifically 5NF. Boyce, Codd and Fagin's work on Normal Forms all deal only...

RalphWilson (3/2/2010)

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If you just arbitrarily do things like using IDENTITY_INSERT or reseed the Identity column, then, IMHO, you deserve to have problems. If you don't screw around with the...

Steve Cullen (3/2/2010)

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An email address is a mutable attribute. As such it would make a terrible primary key for a database.

Just because you use a email address to login...

RalphWilson (3/2/2010)

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An email address is a perfectly reasonable unique identifier provided you have the ability to change it.

David,

You have got to be kindding. Not everyone has an email address...

Tom.Thomson (3/2/2010)

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I'd like to see you explain (a) how you would do this without any sort of NULL and (b) in what sense this two column table is not fully...

Gary Varga (3/1/2010)

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A great example of this is when systems use email addresses as the ID. Unless you maintain your own domain, all it takes is a change in company...

It is a most...

I meant only that that is my experience. I hope the OP will try it for himself rather than take my word for it.

So many business numbers we use are made up. Granted there are items like an ISBN that are regulated, and should provide a strong natural key, but even those...

HowardW (3/1/2010)

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From BOL:

http://technet.microsoft.com/en-us/library/bb510625.aspx

Because the MERGE statement performs a full table scan of both the source and target tables, I/O performance can be affected when using the TOP clause to modify...

To be clear, I'm not saying you should avoid UPDATE FROM just because Microsoft may deprecate it. I'm recommending that you should avoid it because MERGE is more efficient, more...

The Dixie Flatline (3/1/2010)

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David, do you have any source authority that UPDATE is going to be deprecated or is that just a personal opinion? Despite your...

I'm with Gail on this. What you choose as a primary key is not important. Candidate keys are the important issue. Just be sure you are enforcing the candidate keys...

For new code in 2008 I do, yes. The old-style UPDATE with join will likely be officially deprecated in a future version. It is an unpleasant legacy from SQL Server's...