MySQL Error: Cannot add or update a child row: a foreign key constraint fails

Ever got an error like the one below?
Cannot add or update a child row: a foreign key constraint fails (`db01`.<result 2 when explaining filename '#sql-651_3'>, CONSTRAINT `table01_batch_id_foreign` FOREIGN KEY (`batch_id`) REFERENCES `the_batches` (`id`))

Then, there must be some rows with a column value (for batch_id) that is non-existent in the master table. In my case the column (in the child table) was set to DEFAULT value of 0 and obviously a matching id was not found in the master table.

MyWestside – Your portal was never updated after 2009?

MyWestside Profile PageDuring my recent visit to WestSide someone at the checkout told me my existing MyWestside membership card had expired and they issued a new card with a charge of Rs. 150. In order to make sure they entered correct info, I logged into and that is when I came across a really old drop down list for year of wedding. It started from 1900 and ended at 2009! @MyWestside, is there a specific reason behind this? If not, please ask someone to update it. I know several people who got married during 2010, 2011, 2012 and even 2014!

Model Code of Conduct – Polls 2014

From the day I renamed this blog as ‘lets_Do_GoodCode’, I’ve been thinking more of non-code stuff to write about than the code. It takes its own efforts/dedication to come back and write about the code you wrote. Thanks to all those doing it which has helped developers like me world-wide.

I cast my vote!Anyways, I just cast my vote. It took nearly 45 minutes to find the right book that had my name. To my surprise, someone had already taken my voter slip! Walked down straight to the polling booth to find a friendly security guard at the door. He confirmed, there are agents inside with a fresh copy of Book #139. Oh btw, I want to thank that gentleman who was helping everyone to find their new part numbers and roll ids online. I was over-confident of the details printed on my voter card which seem to have changed. Thanks to that man. Honestly, it was all available online at various places and one could find their voter details pretty easily, although some really-old ones were removed.

Malkajgiri lok sabha constituency, to which my voter id belonged, had two EVMs of candidates or they were paged across two EVMs! Anyways, I cast my vote and feel happy. Please go out and vote. Do not get hassled with the crowds around polling stations, we’re a billion and you happen to see more and more people.

Travel with VPN – Around the world in five dollars

World Users
Around the World

Often it becomes challenging to test websites that cater to customers from various countries and regions (e.g for eCommerce portals that accept multiple currencies and region based offers, etc.). Context has become equally important as the customer itself. Because of this, any tool that helps developers to take a quick look at their work through the users eyes would be greatly beneficial for all.

VPN I believe can become one such tool. Web users are already steadily relying on fast VPN services to protect their privacy and identity.

VPN, or a Virtual Private Network, may be familiar to some. It works by creating a secure network connection over a public network (like the internet). Although mainly used for commercial purposes, personal VPN’s are more popular now than ever. With a personal VPN, users are now able to surf the internet more securely and many times, completely anonymously.

I feel that VPN can help development teams a great deal in testing their product behaviour by tunnelling traffic through fast servers across the world such as:

  • How does the home page look when a user hits the site from Belgium?
  • Does currency switcher behave correctly when users hit the site from Europe or South America?
  • Are cookies maintaining an american user’s language and currency preferences correctly when they access the site during travel?

All of these and more offer better insight into user behaviour and interaction with online products and services.

VPN Services have many other uses too. The trend of using VPN products are increasing and it becomes an essential part nowadays for developers to be familiar with their capabilities and how to use it to create, check and deploy new customer solutions. Try it out for yourself. Here are a few VPN Service Providers: