#861 (ok 4.3) Simulate UPDATE queries

[Rik Meijer]

A cool feature would be the possibility to simulate a
UPDATE query, often I have to run such a query on
important data (which I naturally backup first), but it
would spare a lot of time when the query could be
simulated.

An easy fix would be when I have a query like:
UPDATE `important_table` SET
`more_important_row`='newvalue' WHERE
`more_important_row`='oldvalue'

The simulation would be something like:
SELECT *, 'newvalue' as `more_important_row` FROM
`important_table` WHERE `more_important_row`='oldvalue'

As you can see the simulation is only to check the
WHERE part of the query, but may be there are other
uses for it?

[jganders]

Logged In: YES
user_id=1369576

Also See request 1420869.
For InnoDB tables you could issue a rollback after the
update/delete, essentially voiding the transaction.

[Aayush]

will this be something like rollback option in InnoDB for other tables where transactions (if user specifies) will be simulated first and a simulated output will be displayed. so if user commits that then only actual query will be passed to bring change.?
in this way a rollback type property can be simulated in all tables, off course only for one transaction at a time.
please comment if i am getting this right or not??

[Marc Delisle]

Aayush,
you're right.