Ans:

Taking SQL Server as an example, the autonumbered columns are of type Int, and the maximum value is 2,147,483,647, which is more than 2.1 billion. Theoretically, of course, it is possible to reach this maximum value, and if you do, you can't add new rows, and an overflow error will occur. However, in practice it is generally not possible to reach it, because for one thing, applications with such a large amount of data should not be available, and even if they are, they will use optimization methods to classify the data, and for another, the usual hardware environment simply cannot support it.