Will rowid be reused?

Question

In database, such as Informix, DB2, Oracle etc, will the rowid be reused pls?

Answer 1

The RowID are physical location of the data stored on the disk. They are unique for a table. As such they can repeat. If the new record gets stored in the same place (deleting the older one), then rowids would be same (reused).

See this article for details on what rowid consists of in oracle http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/pseudocolumns008.htm

Answer 2

It can be reused:

If you delete a row, then Oracle may reassign its rowid to a new row inserted later.

(See this)

Answer 3

also - be aware it can change if you export and then import your database. you should never store this value as a key as it is unreliable.