I just imported a ton of products for new website that I’m working on, and it turns out that the client misnamed a bunch of images, causing Magento to ignore the image import for those ones. I don’t want to scour through the website and the CSV (and the client wouldn’t want to pay us to do that either), so I figured if I could just come up with a list of SKUs for products missing an image, I could hand it off to them so they could correct everything.

This isn’t foolproof, but it does the job. This query will give you a list of SKUs where there is no record in the database for that product’s ‘image’ attribute (the main large product image).

SELECT `sku` FROM `catalog_product_entity` AS a LEFT JOIN `catalog_product_entity_varchar` AS b ON a.entity_id = b.entity_id AND b.attribute_id = 74 WHERE b.entity_id IS NULL

I was dumping a database today to put onto a different server. I am currently running 5.1.45 locally, and the server I am moving to has 5.0.58. When trying to import the database to the new server, I was getting the following error:

ERROR 1064 (42000) at line 576: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'USING BTREE,
KEY `FK_ATTRIBUTE_VARCHAR_ENTITY` (`entity_id`),
KEY `FK_CATALO' at line 9

After doing some checking around, I found that the problem was the ‘USING BTREE’. Mysql 5.0 and lower doesn’t seem to understand what that is about and will fail. The solution: Just remove ‘USING BTREE’, and you’ll be good to go.

It sounds like versions after mine (5.1.45) have fixed this and omit the ‘USING BTREE’ from the dumps.

I’m not sure if it is possible to make that title much shorter than that… Anyway, I had some old data that I imported to an installation of Magento. All of the product titles were all uppercase, which was quite ugly. I needed a way to convert all of those values to only have uppercase first letter of each word.

Programming that was quite easy, but I noticed that there were also some parts of the string which were not converted like “On/off”, “D.e.”, “Quick-connect”, etc. The ucwords() function doesn’t recognize that kind of stuff. So, I had to find a way around those. I created an array that houses whatever characters you’d like to capitalize after (as long as there is a letter immediately after it). So, those three examples become “On/Off”, “D.E.”, and “Quick-Connect”.

Here’s what I came up with. Feel free to use it if you wish – you’ll just have to change the database credentials, change the SELECT and UPDATE queries to suit your needs, and edit the $also_after array to uppercase after any characters you want:

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<?php
// Database Connection
$db = new mysqli('localhost','username','password','database');
 
// What Ever Query You Want
$query = $db->query("SELECT value_id, value FROM catalog_product_entity_varchar WHERE attribute_id = 45");
 
// Run For Each Result
while ($line = $query->fetch_object()) {
	$value_id 	= $line->value_id;
	$value		= $line->value;
 
	// Populate this array with characters that you want this script to capitalize after.
	// If in the string there is "onn/off", put the "/" character in the array to make "On/Off"
	// otherwise, it would only do "On/off".
	$also_after	= array('-', '/', '(', '.');
 
	// Run this function for each value. Returns new string.
	$string = convert_to_uc($value, $also_after);
 
	// Escape characters for database entry
	$string = $db->real_escape_string($new_string);
 
	// Update the database with your new string
	$db->query("UPDATE catalog_product_entity_varchar SET value = '$string' WHERE value_id = '$value_id'");
}
 
// Convert To Uppercase function
function convert_to_uc($value, $also_after)
{
	$string 	= '';
 
	// Convert thet string to all lowercase, then uppercase the first letter of every word.
	$string 	= ucwords(strtolower($value));
 
	// For each $also_after character, run the uc_match function
	foreach ($also_after as $char) {
		$string = preg_replace_callback('/(\\'.$char.')(\w)/',"uc_match",$string);
	}
 
	// Returns new formatted string
	return $string;
}
 
// Uppercase Match function - used by preg_replace_callback above
function uc_match($match)
{
	return $match[1].strtoupper($match[2]);
}

If you have ever tried to delete a large amount of products out of Magento, you’ll realize that it takes forever, and in many cases, you have to do it in small quantities at a time otherwise it will freeze up. I needed to delete all the products out today but found that I could only delete about 30 at a time. This just wasn’t going to work since there are about 2500 products in the DB. I found something out today by accident that turned out to be extremely helpful.

Due to the nature of the InnoDB mysql engine that Magento uses, and the way they setup their foreign keys, all it takes is one simple mysql command, and mysql will automatically clear out all of the product data from all of the different tables it uses. On top of that, it resets the auto-increment values back to 1 so that you can start off with entity_id 1 again.

I haven’t given it extensive testing, but I checked every table that I knew that stored product information and they were all clear. So, if you need to clear out all your products, open up mysql and just enter this one line in:

TRUNCATE TABLE `catalog_product_entity`;

For more information on how it works, you can visit the Truncate Syntax page on the Mysql website.

Mysqli stands for Mysql Improved. It came out a while ago, I believe with Mysql 4.1.3 and up. There are a lot of great benefits to using mysqli, which I won’t get into now. Maybe later. Here’s just a little to get you started using it:

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<?php
 
// Connect to Database
$db = new mysqli('host', 'username', 'password', 'database');
 
// Perform a query
$items = $db->query("SELECT * FROM cp_items WHERE id > 100");
 
// Run a loop through the results
while($item = $items->fetch_object()) {
    echo '<ul>';
    echo '<li>' . $item->id . '</li>';
    echo '<li>' . $item->name . '</li>';
    echo '</ul>';
}

Connecting to multiple databases at the same time is simple. Just create a new database object, and call the mysqli functions from it. You can read the full documentation of everything available with mysqli to learn more about it.

As I said in the post prior to this, I have really been enjoying using Terminal for accessing MySQL databases. I found a problem with it though. If you have a table with a lot of columns, or a column with a lot of data in it, Terminal will wrap the results of your query making it almost completely unreadable (or a pain to read at best).

I found a work-around. Though it isn’t as good as it could be, it does work. It prevents the wrap, but, everything beyond the right-side of your terminal window is completely removed. It doesn’t give you a scroll bar to see beyond, it is literally gone. If you try to resize your window, you’ll just get blank space.

Why Terminal doesn’t have the ability to turn it on or off is a mystery to me. But, that said, this fix does have it’s place, and it is fairly easy to turn on and off. Here’s what you do:

Open this file: $YOURHOME/.bashrc and place the following in there and save it:

# Wordwrap off
echo -e "\e[?7l\c"

After it is saved, you can close Terminal and re-open it, or restart bash with this command:

. ~/.bashrc

To turn it off again, just remove or comment out the echo statement you added to .bashrc and restart bash again.

If you have any better suggestions for this, please let me know! I’d love to have a better solution.

One of the most popular ways to view and work with a MySQL database is through a web app called phpMyAdmin. There are many other tools out there that you can use, but why use a tool when you’ve already got a command line to work with?

I used to use phpMyAdmin all the time. I eventually found out, through many frustratingly lost hours, that phpMyAdmin doesn’t handle sql dumps very well. So, the next best bet was to do a dump through the command line. Ever since then, I began playing around with the database with the command line, and now it is my preferred method of working with the database.

This post will eventually grow to hopefully be a good reference for myself, and hopefully for you as well. I encourage all of you to learn this stuff. It will be worth it. As for now, the list here will be short, but I hope to grow it. If you have any specific requests, or better ways to do anything I’ve written here, please post a comment.

Connecting to the Database

mysql -u USERNAME -p -h 100.100.100.100 --port 3306 DATABASE;

Explanation:

• -u: Tells mysql that username you want to use
• -p: Tells mysql to prompt you for your password
• -h: Tells mysql what host to use (can be an IP address, or a domain.com)
• ––port: Tells mysql what port to connect to
• DATABASE: This you would replace with what database you want to connect to

If you have connected to the server already via SSH, you do not need to supply the host. You usually don’t need to supply the port, however, there will be cases that you need to supply one (ie: if you are running MAMP or WAMP, the database port is 8889). If the database has no password, you do not need to supply the -p.

Listing the Databases and Tables

#Display the databases
show databases;
 
#Select a database to use
use yourdatabase;
 
#Display the tables of that database
show tables;

Play Around

More to come. If you get connected and select a database to use, play around with what you know. This is all just standard MySQL commands. Try starting out with “SELECT * FROM yourtable;” and see what happens. If you haven’t used the command line before, you’ll be impressed with how the tables are displayed. Have fun!

I ran into a case where I needed to connect to two seperate databases within the same script, and I didn’t know how to do it without closing one connection, and opening another.  With a little time and effort, I figured it out, and it’s quite simple.

Here is the PHP code to connect to a database:

$db1 = mysql_connect('localhost', 'db-user', 'db-password');
mysql_select_db('db-name',$db1);

What this does is store the connection link in the variable $db1. Then you choose which database to you with the second line. With this code, you can then run mysql commands just like this:

$query = mysql_query("SELECT * FROM yourtable;);

Now, in the case where you need to do some work with a different database, you don’t want to be closing and opening connections all the time. So, when you make your database connections, it’s very easy. This is what the code looks like with 3 database connections open (of course, you’d have to change all the variables for each different database):

$db1 = mysql_connect('localhost', 'db-user', 'db-password');
mysql_select_db('db-name', $db1);
$db2 = mysql_connect('localhost', 'db-user', 'db-password');
mysql_select_db('db-name', $db2);
$db3 = mysql_connect('localhost', 'db-user', 'db-password');
mysql_select_db('db-name', $db3);

You will probably want to rename the $db1 varables with something more suggestive of which database you are using just for clarity. Now, to use these different database connections, all you have to do is add that connection link to the end of your query like this:

$query1 = mysql_query("SELECT * FROM yourtable", $db1);
$query2 = mysql_query("SELECT * FROM differenttable ORDER BY column DESC", $db2);
$query3 = mysql_query("SELECT somevalue FROM table WHERE id = 20", $db3);

And that’s all there is to it!