Hi, To solve this you can use the REPLACE command.
Regards, Laercio. -----Original Message----- From: news [mailto:[EMAIL PROTECTED] On Behalf Of Harald Fuchs Sent: quinta-feira, 30 de setembro de 2004 08:25 To: [EMAIL PROTECTED] Subject: Re: (if !update then insert) sequence - result Duplicate key :( In article <[EMAIL PROTECTED]>, "Aleksandr V. Dyomin" <[EMAIL PROTECTED]> writes: > $key='somekeyvalue'; > dbquery("update sometable set count=count+1 where keyfield='$key'"); > if(mysql_affected_rows()<1) > dbquery('insert into sometable set keyfield='$key', count=1'); > --- > First question: this is good method? It's good if you expect the UPDATE normally to succeed. Otherwise, you should first try the INSERT. > Second... My script work on many different hosts with different > hardware, os(only Linux or FreeBSD), and different PHP and MySQL > version. It works fine excepting one thing... Sometime happens errors > like: > MySQL: Duplicate entry 'somekeyvalue' for key 1, query was: insert > into sometable set keyfield='somekeyvalue', count=1 > Why this happens? On some hosts this messageis very rare, but on > others > - so often... I cant understand reason :( You have a race condition: * Client 1 tries UPDATE, sees that it fails * Client 2 tries UPDATE, sees that it fails * Client 1 does INSERT - okay * Client 2 does INSERT - duplictae key error If you think this happens seldom, do the following: 1. Try UPDATE 2. If it fails: try INSERT 3. If it fails due to a duplicate key error: repeat step 1 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
