Hello Rolando, So if I do "INSERT IGNORE INTO `Votes` SET `EntryId`='12345', UserId`='789'"; it *won't* insert the second row if there's a row with EntryId set to 12345 and UserId set to 789? Thanks and sorry!)
-- With best regards from Ukraine, Andre Skype: Francophile My blog: http://oire.org/menelion (mostly in Russian) Twitter: http://twitter.com/m_elensule Facebook: http://facebook.com/menelion ------------ Original message ------------ From: Rolando Edwards <redwa...@logicworks.net> To: Andre Polykanine Date created: , 11:01:40 PM Subject: Insert only if the entry doesn't exist If the table has Primary and/or UNIQUE Keys, then you are fine. You do not need to know what they are. If you want to see them do this: SHOW CREATE TABLE Votes\G INSERT IGNORE INTO does not require ON DUPLICATE KEY options. After all, you said earlier that you want to do nothing if the row exists. Rolando A. Edwards MySQL DBA (SCMDBA) 155 Avenue of the Americas, Fifth Floor New York, NY 10013 212-625-5307 (Work) 201-660-3221 (Cell) AIM & Skype : RolandoLogicWorx redwa...@logicworks.net http://www.linkedin.com/in/rolandoedwards -----Original Message----- From: Andre Polykanine [mailto:an...@oire.org] Sent: Monday, February 14, 2011 3:40 PM To: Rolando Edwards Cc: João Cândido de Souza Neto; mysql@lists.mysql.com Subject: Re: Insert only if the entry doesn't exist Hello Rolando, Sorry, but if I do INSERT IGNORE INTO, then I must indicate a key (typically a unique key or a primary key), or is it false? But I don't know that key and no way to get it without more queries... -- With best regards from Ukraine, Andre Skype: Francophile My blog: http://oire.org/menelion (mostly in Russian) Twitter: http://twitter.com/m_elensule Facebook: http://facebook.com/menelion ------------ Original message ------------ From: Rolando Edwards <redwa...@logicworks.net> To: João Cândido de Souza Neto Date created: , 10:33:05 PM Subject: Insert only if the entry doesn't exist Be Careful. REPLACE INTO mechanically does DELETE and INSERT under mysqld's hood. If you want to do nothing if row exists already then do: INSERT IGNORE instead of REPLACE INTO Rolando A. Edwards MySQL DBA (SCMDBA) 155 Avenue of the Americas, Fifth Floor New York, NY 10013 212-625-5307 (Work) 201-660-3221 (Cell) AIM & Skype : RolandoLogicWorx redwa...@logicworks.net http://www.linkedin.com/in/rolandoedwards -----Original Message----- From: João Cândido de Souza Neto [mailto:j...@consultorweb.cnt.br] Sent: Monday, February 14, 2011 1:39 PM To: mysql@lists.mysql.com Subject: Re: Insert only if the entry doesn't exist Instead of "insert into" you can use "replace into". -- João Cândido de Souza Neto "Andre Polykanine" <an...@oire.org> escreveu na mensagem news:1621362474.20110214201...@oire.org... Hi all, Thanks for your fast answer to my last question! Here's one more problem I commonly deal with. There are cases when I need to insert the row only if such a row doesn't exist, otherwise I need either to update the row or to do nothing, just skip the query. The common case is the rating increment/decrement. I have the + and - links which are AJAX. So I need to prevent fast multiple clicking and over-increasing or over-decreasing the rating of the blog entry. Here's what I'm doing, in a simplified form (assume all of the numbers are PHP variables): "SELECT `Id` FROM `Votes` WHERE `EntryId`='12345' AND `UserId`='789'"; then I'm checking if the user has already clicked a link: if (mysql_num_rows()==0) { "INSERT INTO `Votes` SET `EntryId`='12345', `UserId`='789'"; } else { // do nothing } And here is the question (at last!): How can I MySql'ly check whether a vote does exist and if it does, then insert the row, else either do nothing or update several columns? I assume I can't use ON DUPLICATE KEY UPDATE because I have no unique keys... Hope you understood my problem). Thanks! -- With best regards from Ukraine, Andre Skype: Francophile Twitter: http://twitter.com/m_elensule Facebook: http://facebook.com/menelion -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=redwa...@logicworks.net -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=an...@oire.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
