Big Data, is a concept. Is the whole net Internet data as well as offline data integration, **** enjoy and so on a series of things called data.

These jobs are mainly for data processing, need to learn CSS? By asking this question, you just don't have any foundation in front-end or back-end at all.

Any back-end developer, for the front-end HTML,CSS,JS, etc. must have some understanding. Front-end developers, the back-end development of the program will also have a certain understanding. This is the website development must hold the foundation.

Of course, C++, JV and other development is another environment, different from the website development.

As for what to learn, of course, from the most basic learning. HTML, CSS, JS, PHP or JSP, etc.