This class introduces some theoretical basics of relational databases (those not covered in the database 1 course) required to deal with graph databases and query languages. Database 2 mixes theory and practice, so you will study the theory of query languages as well, as you will learn to setup a DBMS and deal with real-world data and user requirements. The course is composed of two parts: Part 1 (6 CFU): Graph databases and query languages. The student learns the theoretical foundations of graph database modeling and querying. Moreover, the course also covers some technical material; the student learns how to design, create, populate and query a graph DBMS (both RDF and property-graph). Part 2 (3 CFU): Advanced topics. The student learns cutting-edge techniques to access structured data (relational, hierarchical, and graph data) using natural language and extracting information from the text (entity extraction and linking). Moreover, the student learns advanced techniques to deal with data provenance, data pricing, data citation, and data privacy.