Hello everyone.
I am having a problem with orders. I have added a module to insert greeting card for the products. Sometimes with the order the greeting text is missing. I have added checks using javascript, but sometimes I still have the problem.
How can I put checks from the backend? it should be able to check if column oxselvariant exists then it should check if column oxpersparam has a value.
Hello 
I would try to reproduce the error. If you can reproduce the bug, you should be able to catch it.
Frontend and backend logic are partly separated there. If the backend logic is in a model class, you can use this via a module overload for the frontend and define your own method.
Best,
Tim
Problem is that I have been trying to reproduce the error, but I am unable to figure out what is causing the error.
To solve the problem you have to be able to reproduce it as long as nobody can solve the problem.
The only thing that helps is intensive debugging and / or having someone else test it.