Hi there I am busy evaluating InnoDB to decide whether to use it in our live environment, simultaneously (which proberly isn't the best thing) I am making changes to my code (I am using Visual Basic), to stream line my transactions and make full use of the "transaction" facility.
My question to you is this: I am running with AutoCommit set to 1, but every time I am going to update an invoice I set it to 0, execute the tranactions queries updating in the region of 8 inno db tables while readnig some information from other InnoDb tables/Mysql Tables, then I commit and reset AutoCommit to 1. Part of my transactions are queries like "Update GenMas2002 Set Balance1=Balance1 + 500 where code='150100'" Now, my question is, what happens with a query above running simulatenously with another similar query, and then the first query is rolled back. I.e. if Balance1 was $100, the first query would then assume $100 + $500, the second query would assume ????? would it be $600 or would it too assume $100? I am guessing it would assume $100 as mysql is set to READ COMMITED, and therefore it would not have seen the first transaction yet as it was either not yet comitted, or rolled back. So if the first query is then updated after the second query what would happen? It's timestamp is less than query two, yet query two has already updated the table, so would query one still pick up $100 or would it read the $600 after the query two transaction????? Is this the right way to do this? i.e. using the "update .... balance1=balance1 + 500" in side a transaction which has the potentially to be rolled back and there could be any number of simulatenous queries of this nature executing on the same row in the same table at once? Regards Warren ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Warren van der Merwe Software Director PRT Trading (Pty) Ltd t/a RedTie Durban, South Africa Cell (+27-83) 262-9163 Office (+27-31) 767-0249 Any views expressed in this message are the sender's own, and do not represent the views of RedTie Software except where the sender specifically states them to be the views of RedTie Software. This e-mail should only be read by those persons to whom it is addressed. Accordingly, we disclaim all responsibility and accept no liability (including in negligence) for the consequences of any person other than the intended recipients acting, or refraining from acting, on such information. If you have received this e-mail in error, please accept our apologies and we simply request that you delete this document. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and/or publication of this e-mail is strictly prohibited. --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
