Re: Getting the first row from a select

On 3 Oct 1998, Christopher Browne wrote:

> ROWNUM is, in Oracle, effectively the physical location of the entry.
> Kind of like your telephone number; just because we just asked for the
> "B's" doesn't mean that the phone number gets reset to 1...

I think you are referring to ROWID, which in Oracle7 was of the form "block.slot.file," and in Oracle8 is an opaque identifier that can be decoded to provide the block, slot, and file of a row.

ROWID isn't really "assigned" at any time, but is rather more like an address than the phone number in your analogy. It just means "this is where the row is actually stored in the database." Indexes do physically store rowids for purposes of referencing a table row. Can anyone tell the other type of segment that uses rowid references?

ROWNUM, on the other hand is just the counter of rows returned by a query.

--
Jeremiah Wilton      http://www.wolfenet.com/~jeremiah