Re: MUTEXes in PLSQL?
From: DJH <NOSPAM_at_NOSPAM.COM>
Date: Sat, 16 Feb 2008 08:38:23 -0500
Message-ID: <13rdpqitpe3k85e@news.supernews.com>
>> 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
Date: Sat, 16 Feb 2008 08:38:23 -0500
Message-ID: <13rdpqitpe3k85e@news.supernews.com>
DA Morgan wrote:
> 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.
Thanks DA but I get his error:
I am using a select count() statement with 'for update' in a trigger.
ORA-01786: FOR UPDATE of this query expression is not allowed Received on Sat Feb 16 2008 - 07:38:23 CST