Unless you specify an order that differentiates between each row, Oracle will give you the data back in "no specific order". If all your data is in a single block then it will appear that the order is fixed, until a time when the data is no loger contained in a single block.

The thing to remember here is, "If you want it in a specific order use an ORDER BY clause that *guarantees* that order, rather than relying on guesswork."

Cheers

Tim...