If you have an auto incrementing number, you've just described exactly what it is supposed to do, it does not reuse numbers. If you want it to fill in the holes, then you would need to not use an auto increment, and do a routine that works out the holes in your numbers list to find which numbers it can put in.
As for the key being 000001, that comes down to formatting.
Neither of these is specific to c# or SQL 2008
LizR
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Sivak, your post has nothing to do with this thread.
LizR
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set identity seed to be able to change the 1 to a different number
the padding with 0's is formatting, do it code side or in query, not store numbers in a database like that
dickersonka
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