Hello, This is my very first post here, good day. I post it here because I'm afraid I may post it into the wrong category. I would to like to ask for advice: 1. How do we choose what database technology to use? What are the parameters do we usually need to consider? 2. When it comes to unstructure data, what do you think would be the best database that we could use nowadays with a very reasonable price? 3. When we build a software, how do we determine what would be the minimum hardware requirements? Are there any tools we can use to help on this? Thank you.