To know the exact timing

Question

hi all,
1)How can i know that
in a oracle 10g table when i modified a row or deleted a row and which row i have inserted when
i want to know the particular time.
can it is possiable if possiable then tell me how.
2)what is the difference between raise_application_error and raise ?
3) Is there any difference between oracle 9i merge command and 10g merge command ?

Answer 1

Here is a cool tidbit of information from .....
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/pseudocolumns007.htm#sthref825
ORA_ROWSCN Pseudocolumn For each row, ORA_ROWSCN returns the conservative upper bound system change number (SCN) of the most recent change to the row. This pseudocolumn is useful for determining approximately when a row was last updated. It is not absolutely precise, because Oracle tracks SCNs by transaction committed for the block in which the row resides. You can obtain a more fine-grained approximation of the SCN by creating your tables with row-level dependency tracking. Please refer to CREATE TABLE ... NOROWDEPENDENCIES | ROWDEPENDENCIES for more information on row-level dependency tracking.
And then from ....
http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14251/adfns_flashback.htm#sthref1467
ORA_ROWSCN is a pseudocolumn of any table that is not fixed or external. It represents the SCN of the most recent change to a given row, that is, the latest COMMIT operation for the row. For example:
SELECT ora_rowscn, last_name, salary
FROM employees
WHERE employee_id = 7788;
ORA_ROWSCN    NAME    SALARY
*202553 Fudd 3000*
The latest COMMIT operation for the row took place at approximately SCN 202553. You can use function SCN_TO_TIMESTAMP to convert an SCN, like ORA_ROWSCN, to the corresponding TIMESTAMP value.
See what you can find when you search the documentation?
Regards
Tim