Re: MUTEXes in PLSQL?

DJH wrote:
> I am writing a trigger to calculate the value of a column in a row in a
> another table in processing the current trigger for a different table.
> I need to make sure that the row in the other table is not updated by
> other processes while I am processing this trigger.
>
> How may I do that?
>
> Also can you run a "select count(*) where .." on the current table you
> are processing in the trigger without getting "mutating.. type errors."
>
> I am using 10G.
>
>
> I need to check the inventory of the item before I can let the order
> through but also I need to check current order table to see if there are
> any unprocessed orders that pre-reserved the same items from the inventory.
>
> So total available items in inventory will be Inventory Items -
> Unprocessed Order PreReserved Items.
>
> If available items are not there to process current order I have to
> prevent it from going through. Meanwhile I cannot let anyone update
> the Inventory until I finish inserting the order with its pre-reserved
> items.
>
> Thanks

SELECT *
FROM second_table
WHERE some_condition
FOR UPDATE; Read the docs before you do this so you fully understand what is happening.

-- 
Daniel A. Morgan
Oracle Ace Director & Instructor
University of Washington
damorgan_at_x.washington.edu (replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org