Updating multiple fields mysql
A requirement arises in many systems to update multiple SQL database rows.For small numbers of rows requiring updates, it can be adequate to use an UPDATE statement for each row that requires an update.But in many cases this only provides a modest improvement as each UPDATE operation still requires a round-trip communication with the database server.In the case where the application server and database server are on different hosts, the round-trip will involve network latency as well.Discuss using ASP 3 to work with data in databases, including ASP Database Setup issues from the old P2P forum on this specific subtopic.
A more effective solution to this problem is to attempt to reduce the number of UPDATE statements.
CREATE TABLE `ips` ( `id` int(10) unsigned NOT NULL DEFAULT '0', `begin_ip_num` int(11) unsigned DEFAULT NULL, `end_ip_num` int(11) unsigned DEFAULT NULL, `iso` varchar(3) DEFAULT NULL, `country` varchar(150) DEFAULT NULL ) ENGINE=Inno DB CREATE TABLE `country` ( `countryid` tinyint(3) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL, `ordering` smallint(5) unsigned NOT NULL DEFAULT '0', `iso` char(2) NOT NULL, PRIMARY KEY (`countryid`) ) ENGINE=Inno DB Using My SQL update multiple table syntax: 14.2.11 UPDATE Syntax Note that you have two different lengths and data types on your iso columns.
There are, in fact, two separate sets of ISO codes, 2-letter and 3-letter, so you may not in reality be able to join these columns: ISO 3166-1 The join condition There is a difference in behavior to my version - your version will set it to NULL if it's not found, mine will not alter an existing value if it's not matched. Also the execution plan may differ depending upon the [email protected] It's probably not a problem - when you add the new column, I'm assuming it will be NULL and also a foreign key, so invalid entries wouldn't be allowed anyway.
The UPDATE statement requires a few items of information in order to operate.
Firstly, it needs the name of the table that is to be updated.