Difference between Rowid and Rownum ?

ROWID

A globally unique identifier for a row in a database. It is created at the time the row is inserted into a table, and destroyed when it is removed from a table.'BBBBBBBB.RRRR.FFFF' where BBBBBBBB is the block number, RRRR is the slot(row) number, and FFFF is a file number.

ROWNUM

For each row returned by a query, the ROWNUM pseudo column returns a number indicating the order in which Oracle selects the row from a table or set of joined rows. The first row selected has a ROWNUM of 1, the second has 2, and so on.

You can use ROWNUM to limit the number of rows returned by a query, as in this example:

SELECT * FROM employees WHERE ROWNUM < 10;

Rowid	Row-num
Rowid is an oracle internal id that is allocated every time a new record is inserted in a table. This ID is unique and cannot be changed by the user.	Row-num is a row number returned by a select statement.
Rowid is permanent.	Row-num is temporary.
Rowid is a globally unique identifier for a row in a database. It is created at the time the row is inserted into the table, and destroyed when it is removed from a table.	The row-num pseudocoloumn returns a number indicating the order in which oracle selects the row from a table or set of joined rows.