Sometimes it is critical to ensure a group of queries are all executed successfully to maintain the integrity of our data. Let's say we have a banking app where we need to subtract funds from one account and add funds to another:

copyraw
$mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'-1000000 WHERE 'user' = 'Bob'");
$mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'+1000000 WHERE 'user' = 'Fred'");
  1.  $mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'-1000000 WHERE 'user' = 'Bob'")
  2.  $mysqli->query ("UPDATE 'accounts' SET 'balance' = 'balance'+1000000 WHERE 'user' = 'Fred'")

What if one of the queries fails? To mitigate the chances of misplacing our millions due to some possible error we must ensure that both queries are executed with the expected result before committing any changes to the data. This where transactions are useful. We can run the queries, then check if some conditions are met before committing the changes in the data:

Category: MySQL :: Article: 644

What?
A quick article on how to trim in MySQL along with getting rid of any leading or trailing tab characters.

Why?
I use MS Excel for organizing data and then converting to MySQL commands. Unfortunately, the MS Excel software adds tab characters to delimit the columns...

How?
UPDATE `mytable` SET `myColumn` = TRIM(CHAR(9) FROM TRIM(`myColumn`));
Source: Stack Overflow - How to Remove Tabs

What?
A quick article showing my MySQL statement when I want to remove all the accents from foreign characters and return the English equivalent.

Why?
A content management system (CMS) that I'm working on has just gone international and started including the names of places in other countries. This is nice but its search engine doesn't work properly as it thinks "riviere" is different to "rivière". We need to ensure that a search for any of these kind of words will return results of similarly typed/sounding words.

How?
Here's just a splurge of SQL but I use this often enough:

What?
A quick article on how to populate a database column from another table using a string comparison.

Why?
I have several database tables which replicate country names and I would rather they all use the ccTLD two letter code. This article was written because it took me so long to work it out.

How?
UPDATE  `table_to_update` a
        INNER JOIN `table_to_read` b
            ON a.`CountryName` COLLATE utf8_general_ci LIKE b.`CountryName` COLLATE utf8_general_ci
SET     a.`ccTLD` = b.`ccTLD` 

Applies to:
  • MySQL Database v5.0.45
  • MySQL Workbench v6.0.8.11354 build 833

What?
This is a quick article on how to get around the problem of backing up your MySQL database when attempting to "Data Export" using MySQL Workbench. This is not regarding the connection issue as I can connect to my database using MySQL Workbench (I have enabled the old authentication protocol). The error ONLY appears when I try to "data export" the database.

Why?
The quick solution for everyone else is to change/reset the password of the connecting database user, but herein lies the problem. When you read my workaround, you'll say that I haven't solved anything; but this is a production database I want to export for offline backup. I have to raise and log a formal change request and follow a workflow process in order to make a change on a live system to a service user account... Especially one used by the scripts to access the database-driven website.

How?

What?
So this is an article exploring how to convert UPPERCASE text into mixed case. The feed is originally for a personnel feed so it won't be converting long paragraphs of English text. Instead it will be applied to names and addresses as well as job titles and departments.

Why?
We wanted a T-SQL version despite having successfully built a custom script component for SSIS.

How?
You can search my site for how to do this in VB or C#. This version is entirely using T-SQL and we're going to use a function so no dynamic SQL (execute, evaluate).

Credit where Credit is Due:


Feel free to copy, redistribute and share this information. All that we ask is that you attribute credit and possibly even a link back to this website as it really helps in our search engine rankings.

Disclaimer: The information on this website is provided without warranty and any content is merely the opinion of the author. Please try to test in development environments prior to adapting them to your production environments. The articles are written in good faith and, at the time of print, are working examples used in a commercial setting.

Thank you for visiting and, as always, we hope this website was of some use to you!

Kind Regards,

Joel Lipman
www.joellipman.com

Related Articles

Joes Revolver Map

Joes Word Cloud

user   report   creator   select   need   uploaded   note   function   zoho   parameter   mysql   version   program   table   where   joomla   code   files   work   source   following   value   date   windows   would   order   form   data   first   search   time   script   website   error   using   google   server   list   page   license   find   deluge   database   added   could   used   system   file   display   name   JoelLipman.Com

Accreditation

Badge - Certified Zoho Creator Associate
Badge - Certified Zoho Creator Associate

Donate & Support

If you like my content, and would like to support this sharing site, feel free to donate using a method below:

Paypal:
Donate to Joel Lipman via PayPal

Bitcoin:
Donate to Joel Lipman with Bitcoin - Valid till 8 May 2022 3QnhmaBX7LQSRsC9hh6Je9rGQKEGNQNfPb
© 2021 Joel Lipman .com. All Rights Reserved.