Nevyn (4/28/2015)

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Sergiy (4/27/2015)

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MAC address - is it a string?

By all means - NO!

Compare E8:AB:... and e8-ab-...

These are completely different strings, but they present the same MAC address.

Just another example of an identifier which cannot be stored as a string.

As much fun as it is to see people pushing back on Mr Celko, and as much as I may disagree with a few of his examples,

create table #test

(

minimac varchar(5) PRIMARY KEY CLUSTERED

)

GO

insert #test (minimac) values ('E8:AB')

GO

insert #test (minimac) values ('e8:ab')

GO

-- d r o p table #test

Violation of PRIMARY KEY constraint 'PK__#test_____40C5B956C93DE1AB'. Cannot insert duplicate key in object 'dbo.#test'. The duplicate key value is (e8:ab).

The strings aren't completely different as far as SQL server is concerned except with specific collations.

Just sayin'