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Book Overview & Buying
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Table Of Contents
What's New in SQL Server 2012
You are no doubt used to IDENTITY and how this works with a seed and increment value. SEQUENCE is structured in a very similar way, but with fewr limitations, giving it a welcome flexibility.
A SEQUENCE object is created at the database level but, unlike an IDENTITY property, it can be used across multiple tables. An IDENTITY value is generated when you insert a row into a table and it cannot be updated. You can retrieve the SEQUENCE value at any time and reset it without altering its previous value, and even set a minimum and maximum value. Let us look at a simple example:
CREATE SEQUENCE mySequence AS int START WITH 1 INCREMENT BY 1
As you can see, mySequence is now available for use by all tables in the database:

We have not used the SEQUENCE object yet, so the first value returned should be 1. Run the following statement to confirm this:
SELECT NEXT VALUE FOR mySequence AS [Next Value]
We can see that the SEQUENCE has not been used:

Next we will create a table so we can put SEQUENCE...
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