Does SQL Server guarantee sequential inserting of an identity column?

Question

In other words, is the following \"cursoring\" approach guaranteed to work:

1. retrieve rows from DB
2. save the largest ID from the returned records for later,

Answer 1

I think this can go wrong depending on the duration of transactions Consider the following sequence of events:

1. Transaction A starts
2. Transaction A performs insert - This creates a new entry in the identity column
3. Transaction B starts
4. Transaction B performs insert - This creates a new entry in the identity column
5. Transaction B commits
6. Your code performs its select and sees the identity value from the 2nd transaction
7. Transaction A commits -

The row inserted by Transaction A will never be found by your code. It was not already committed when step 6 was performed. And when the next query is performed it will not be found, because it has a lower value in the identity column than the query is looking for.

It could work if you perform the query with a read-uncommitted isolation mode