Tech.Bitez » MySQL

Upgrading MySQL 4

Wasif — Fri, 08 Jan 2010 18:00:17 +0000

Today I found a couple of useful articles about upgrading MySQL 4. One is written by Peter Zaitsev and other by Guillaume Lefranc.

They are talking about problems you may face while upgrading as well as benefits of MySQL 5.

I hope you guys can really benefit from it.

MySQL 5.0.77 in RHEL 5/CentOS 5

Wasif — Wed, 14 Oct 2009 18:51:10 +0000

Red Hat Enterprise Linux 5 and CentOS 5 are now shipping MySQL 5.0.77 instead of MySQL 5.0.45 on security grounds.

This is moderate security release according to RHEL and CentOS.

MySQL for online applications – Webinar Series

Wasif — Sat, 15 Aug 2009 20:49:10 +0000

MySQL.com is conducting webinars on its usage in online applications. It is a series of 5 webinars i.e.

Part 1: Introduction to MySQL Scale Out and Replication Services
In the first installment we look at the basics for deploying MySQL for a scalable online application such as:

Choosing the right architecture
Scale Out - What, Why and How?
Using MySQL Replication Services
MySQL Solutions to help manage your high-growth business

North America -- Tuesday, August 18, 2009: 10:00 Pacific time / 1:00 Eastern time

EMEA -- Wednesday, August 26, 2009: 10:00 am European Central Time

Count number of words in a MySQL column

Wasif — Tue, 01 Jul 2008 17:36:15 +0000

It is a common requirement to count number of words in a column of a MySQL database table. But MySQL does not have any built in function to count number of words as it usually has for number of purposes.

But you can do it without it with a simple trick e.g. you have a column name and want to count number of words in it. This query will return number of words separated with space in a column

SELECT SUM( LENGTH(name) - LENGTH(REPLACE(name, ' ', ''))+1)
FROM table

If you want to count number of words separated by some other string for example comma (,) or semicolon (;), simply replace space with your required character.

MySQL GUI Tools

Wasif — Thu, 01 May 2008 10:31:45 +0000

I am creating a list of MySQL GUI (front end) tools. I hope you will contribute this list.

A wide variety of MySQL GUI tools are available in the market. Most of them are free but some are paid as well. We can divide GUIs in 2 categories i.e. desktop and web based applications. Here is the list of popular MySQL GUI tools I have heard of

Desktop Application
- MySQL Workbench
- Old official MySQL GUI Tools (Linux, Windows, Mac OSX)
- HeidiSQL
- dbForge Studio (requires .NET Framework 2.0, 3.0 or 3.5)
- Navicat (Linux, Windows, Mac OS X)
- SQLyog
- CocoaMySQL (Mac OS X)
- SQL-Front
- Toad for MySQL
- ACDB sql client - Supports MySQL and Oracle
- Aqua Data Studio (Linux, Windows, Mac OS X, Solaris)
- DreamCoder (Windows)
- DBACentral (Windows)
- SQL Manager (http://www.sqlmanager.net/de/products/mysql/manager)
- DatabaseSpy
Web Based Application

If you know any good GUI Tool, please let me know.

Saving images in MySQL with PHP

Wasif — Wed, 18 Jul 2007 18:33:53 +0000

People have different opinions on saving images in database. Some says, "Why bother database if we can handle this by saving images to disk". I am agree with this;).

Most of the requirements can be fulfilled by saving the images to disk. This reduces the unnecessary load on MySQL.

Here is the small code to save the image in MySQL with the help of PHP.

Images are saved in MySQL as BINARY data. BINARY data can not be saved in varchar or char data types, for this purpose we need a data type which can handle binary data. BLOB columns are treated as binary strings (byte strings). The following table is fulfilling our requirements for a simple test with a BLOB field.

CREATE TABLE `images` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `image` MEDIUMBLOB NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM;

Now we have a MySQL table ready to store the image. Next steps are easy i.e.

Read the image
Encode the image data
Save binary data in DB

These 3 steps are performed with the following PHP code

$image = chunk_split(base64_encode(file_get_contents("image.jpg")));
$query = "INSERT INTO images (image) VALUES('$image')";
mysql_query($query) or die(mysql_error());
echo "Image id is ".mysql_insert_id();

Now we have saved the image in database successfully. The next step is to display the image.

// showimage.php
header('Content-type: image/jpeg');
$query = "SELECT image from images where id=1";
$rs = mysql_fetch_array(mysql_query($query));
echo base64_decode($rs["image"]);

Ohhh!!! You wanted to display the image in HTML page. No problem, call this file as a image in .e.g.



</span></a></span>Image Test<span style="color: #009900;"><span style="color: #000000; font-weight: bold;">

 

Displaying image from database
 
 src="showimage.php" />

Download multiple files upload script

Let me know if you need some more info on this topic.

Download data as csv using PHP

Wasif — Sat, 30 Jun 2007 23:05:50 +0000

This is a very simple example to download data in csv format using PHP and MySQL. I have used a table with two columns i.e. id and name.

The main point to download file is a proper use of header(). It has said many times in many places but I repeat here, "Make sure there must not be any sort of output (including whitespaces) before header()". We can also set a default file name for the file.

Here is the PHP code


// Connect to database
mysql_connect("localhost", "root", "root");
mysql_select_db("test");
 
// mention the file name to display in download prompt
$file_name = "download.csv";
 
header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"$file_name\"");
header("Cache-Control: cache, must-revalidate");
header("Pragma: public");
 
// Output header
echo "Id,Name"."\n";
 
$result = mysql_query("SELECT * FROM test");
while($rs = mysql_fetch_array($result))
{
	echo $rs["id"].",";
	echo $rs["name"]."\n";
}
?>

Consider the followings when downloading a large csv file

PHP script may exceed maximum execution time. To prevent this, use set_time_limit() at top of the script.
Sometimes it is beneficial to use mysql_unbuffered_query() instead of mysql_query() for huge data.

If you find any problem with this code, please inform.

Note: Do not use "ID" in the start of CSV file. Doing so will result in an error "SYLK: File format is not valid" when opening this file in Microsoft Excel.