In a database such as Informix, DB2, Oracle, etc., will reidid be reused PLS?
RowID is the physical location of the data stored on disk. They are unique to the table. As such, they may recur. If the new record is saved in the same place (deleting the older one), then the rowids will be the same (reused).
See this article for details on how rowid consists of oracle http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/pseudocolumns008.htm
It can be reused:
If you delete the row, then Oracle can reassign its rowid to the new row inserted later.
(see this )
also - remember that it can change if you export and then import your database. you should never save this value as a key, as it is unreliable.