My question is about software engineering/programming related fields, but don't know maybe it can be applied to other fields as well.
If I read a couple introductory books on a technology, for example about NoSQL databases, wrote some code on my own to learn, will it be appropriate to add it to my CV, or mention it during an interview, to denote I know a little bit about it, even though I have never used that technology at my previous jobs/projects professionally?
If you have just studied the technology in your own time, I'd be wary about adding it to your CV.
When applying for a job the main thrust of a CV is to highlight your role within a project to demonstrate what you actually did during your time at the previous company. The technologies used, while important, are not always necessary. You should include relevant technologies on your CV, but these would usually be ones you have used professionally for a year (or at least several months) or more.
Having said that, if the role is something like a technical lead then it is important that you have experience in using those technologies in a professional setting.
There is no harm in adding a section that is clearly marked as technologies that you have studied outside work to show that:
If there is no space on your CV or the form you fill in, then mentioning it at the interview would be the better approach. However, you need to make sure that you mention it at an appropriate time - when discussing ongoing education for example.
I put such information on my first one; your profile suggests you are learning to code. The interviewers at one of the largest computer retailers (at the time) asked about it and was impressed, it was definitely a factor in their consideration of my otherwise fairly blank resume.
They called upon the skills I outlined often, as the other employees were lacking in such skills; save for one other person whom was quite busy.
He gave me a letter of reference and hooked me up with my second interviewer when I left. Other than adding the prior employer my resume remained the same. I aced that interview too, my second interview was only to offer the position.
I stayed there for years and took a couple of shorter term jobs after that. I accumulated enough money to go to one of the leading schools in this half of the country.
With a few jobs and some impressive schooling I removed this now dated and mostly irrelevant information and that only lead to fewer questions.
So if your young, and don't have a lot to show, relevant additional information can be useful. As your experience matures these 'signs of inexperience' have no place on your resume unless you like more questions or the information is particularly relevant (EG: In your case, "Owned and programmed a computer for the past 10 years" - assuming that's true).
You can write anything you want on your resume, I've seen some outrageous claims.
But studying on your own means little without certification. So if you want to be taken seriously, study towards a cert and get it.
