Over the summer I used three different types of databases. My program had to communicate with Apache Solr, Cassandra and Microsoft SQL databases. In order to increase the speed of my programs, I used more specific queries in my programs so that the programs themselves would do less processing. For example, if I am compiling an alert with articles from a specific time frame, I could include time information in my query so that my program wouldn't have to parse through every single article and then filter afterwards. All of this to say that I have some experience with this and I haven't learned much so far. The only new thing for me is emacs and the use of the terminal (we used IDEs).