http://albertech.net Guides and Reviews for WordPress, PHP, MySQL, Apache, CMS Systems, jQuery, and other Technologies Tue, 31 Jan 2012 17:31:44 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 http://albertech.net/2011/10/upgrading-debian-lenny-to-squeeze-with-mysql-for-row-based-replication/ http://albertech.net/2011/10/upgrading-debian-lenny-to-squeeze-with-mysql-for-row-based-replication/#comments Fri, 28 Oct 2011 22:46:56 +0000 admin http://albertech.net/?p=820
I completed an upgrade of Debian Lenny to Squeeze on a production database server over the weekend. It went quite well and I had zero downtime thanks to my secondary database servers running in-place. One of the biggest benefits to running Squeeze is that MySQL runs at version 5.1.49. Lenny only supports up to MySQL 5.0. Row-based-replication is safer to replicate data to other servers since all changes are replicated. Prior to MySQL 5.1.14, updates to the mySQL database were not replicated. They were updated via statements (e.g. GRANT, REVOKE). This can potentially cause data-consistency between the master and ... ]]> http://albertech.net/2011/10/upgrading-debian-lenny-to-squeeze-with-mysql-for-row-based-replication/feed/ 1 http://albertech.net/2011/01/mysql-stats-find-number-of-rows-in-a-database/ http://albertech.net/2011/01/mysql-stats-find-number-of-rows-in-a-database/#comments Tue, 11 Jan 2011 00:48:52 +0000 admin http://albertech.net/?p=558 If you ever have the need to find the answer to the following:

• What are the number of tables in a MySQL database?
• What are the number of rows in a MySQL database?
• How much space is the MySQL database using up on the server?
• How many tables there are in a MySQL server?
• How many rows there are in a MySQL server?

One of the quickest ways to find out MySQL reporting stats is using PHPMyAdmin. The software is usually installed on a number of servers by default, so its just a matter of locating where in the program to find this info. This is an example of what the stats look ... ]]> http://albertech.net/2011/01/mysql-stats-find-number-of-rows-in-a-database/feed/ 1 http://albertech.net/2010/07/disable-autostart-of-mysql-in-debian-and-ubuntu/ http://albertech.net/2010/07/disable-autostart-of-mysql-in-debian-and-ubuntu/#comments Wed, 07 Jul 2010 17:39:43 +0000 admin http://albertech.net/?p=427 sysv-rc-conf (Install it using aptitude or apt-get install)]]> http://albertech.net/2010/07/disable-autostart-of-mysql-in-debian-and-ubuntu/feed/ 0 http://albertech.net/2010/04/fix-mysql-error-illegal-mix-of-collations/ http://albertech.net/2010/04/fix-mysql-error-illegal-mix-of-collations/#comments Mon, 12 Apr 2010 20:00:49 +0000 admin http://albertech.net/?p=395 The error message looked like: "Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (utf8_general_ci,IMPLICIT) for operation 'find_in_set'" I ran into this problem today while importing text from a CSV file. Evidently, the text format of the document had UTF characters, which caused CodeIgniter to error out when it tried to insert it to the database. The line had French characters (The ç in Français) My database fields by default are set to "latin1_swedish_ci" character set. The fix? I decided the best way to fix this was to set the Collation option for that specific field in the MySQL database to  "utf8_general_cihttp://albertech.net/?p=372 http://albertech.net/2010/03/mysql-case-insensitive-order-by/feed/ 5 http://albertech.net/2010/01/mysql-tutorial-fetch-last-10-rows-without-reversing-order/ http://albertech.net/2010/01/mysql-tutorial-fetch-last-10-rows-without-reversing-order/#comments Tue, 05 Jan 2010 21:57:39 +0000 admin http://albertech.net/?p=330 SQL Command $sql = "SELECT * FROM (SELECT * FROM [TABLE] WHERE ORDER BY modified_date DESC LIMIT 10) AS tbl ORDER BY tbl.modified_date" This will retrieve the last 10 rows while sorting by date chronologically. I used this SQL command for ... ]]> http://albertech.net/2010/01/mysql-tutorial-fetch-last-10-rows-without-reversing-order/feed/ 2 http://albertech.net/2009/07/mysql-avoiding-the-mysqltoo-many-connections-error/ http://albertech.net/2009/07/mysql-avoiding-the-mysqltoo-many-connections-error/#comments Fri, 17 Jul 2009 19:37:56 +0000 admin http://albertech.net/?p=208 http://albertech.net/2009/07/mysql-avoiding-the-mysqltoo-many-connections-error/feed/ 3 http://albertech.net/2009/06/quick-tuning-mysql-performance/ http://albertech.net/2009/06/quick-tuning-mysql-performance/#comments Fri, 12 Jun 2009 01:32:24 +0000 admin http://albertech.net/?p=186 http://albertech.net/2009/06/quick-tuning-mysql-performance/feed/ 2 http://albertech.net/2009/03/wordpress-mu-27-review/ http://albertech.net/2009/03/wordpress-mu-27-review/#comments Wed, 18 Mar 2009 00:42:58 +0000 admin http://albertech.net/?p=122 http://albertech.net/2009/03/wordpress-mu-27-review/feed/ 7 http://albertech.net/2009/03/preventing-mysql-injection-with-php/ http://albertech.net/2009/03/preventing-mysql-injection-with-php/#comments Thu, 12 Mar 2009 22:13:14 +0000 admin http://albertech.net/?p=110 A good practice is to check input strings to make sure users don't put in mySQL commands in your server. For instance, if a username or password POST variable isn't filtered, there is a potential for an injection like 'OR myusername='. In the past, I've been using my own PHP toolkit to "clean" the input variables. But recently, I began searching to see if there are a built-in solution in PHP for this, especially since I'm converting a script written in Python that had the filter MySQLdb.escape_string. Enter mysql_real_escape_string()]]> http://albertech.net/2009/03/preventing-mysql-injection-with-php/feed/ 1 http://albertech.net/2009/03/converting-mysql-datetime-to-any-format/ http://albertech.net/2009/03/converting-mysql-datetime-to-any-format/#comments Sun, 01 Mar 2009 05:54:59 +0000 admin http://albertech.net/?p=95 MySQL 5.1 SELECT DATE_FORMAT manual For instance, if you wanted to convert the datetime into something that reads function ConvertNiceDateOnly($date) { // Convert mySQL date to nice formatted date $normaldate = mysql_query("SELECT DATE_FORMAT('$date','%M %e, %Y')"); $normaldate = mysql_fetch_row($normaldate); $normaldate = $normaldate[0]; return $normaldate; } ]]> http://albertech.net/2009/03/converting-mysql-datetime-to-any-format/feed/ 0 http://albertech.net/2009/01/php-mysql-datetime-to-seconds/ http://albertech.net/2009/01/php-mysql-datetime-to-seconds/#comments Tue, 27 Jan 2009 02:53:51 +0000 admin http://albertech.net/?p=59 $unixseconds = strtotime($mysqldate); For instance, you can use this to write a timeout script for login failures. Usually, a system should lock after 3-5 consecutive failed login attempts. I save the timestamp after the 5th consecutive login failure, then run a check on this timestamp if the current time is within the ~5-10 minute lockout window. 5 minutes is 300 seconds, 10 minutes is 600 seconds.]]> http://albertech.net/2009/01/php-mysql-datetime-to-seconds/feed/ 0 http://albertech.net/2008/12/mysql-rename-a-database/ http://albertech.net/2008/12/mysql-rename-a-database/#comments Tue, 30 Dec 2008 19:16:31 +0000 admin http://albertech.net/?p=51 mysqladmin create [Name of new database] mysqldump --opt [Name of old database] | mysql [Name of new database]]]> http://albertech.net/2008/12/mysql-rename-a-database/feed/ 0 http://albertech.net/2008/12/reset-mysql-auto-increment-to-1/ http://albertech.net/2008/12/reset-mysql-auto-increment-to-1/#comments Thu, 11 Dec 2008 20:04:10 +0000 admin http://albertech.net/?p=47 delete ALL rows in a table. This is useful in case you had to do some testing and wanted to reset the primary key field back to 1 and clear out the table. truncate table [NAME OF TABLE] If you don't want to wipe out the table, you can reset the auto_increment by using: alter table [NAME OF TABLE] auto_increment=1]]> http://albertech.net/2008/12/reset-mysql-auto-increment-to-1/feed/ 0