Chapter 5. Scala and SQL through JDBC

One of data science's raison d'être is the difficulty of manipulating large datasets. Much of the data of interest to a company or research group cannot fit conveniently in a single computer's RAM. Storing the data in a way that is easy to query is therefore a complex problem.

Relational databases have been successful at solving the data storage problem. Originally proposed in 1970 (http://www.seas.upenn.edu/~zives/03f/cis550/codd.pdf), the overwhelming majority of databases in active use today are still relational. In that time, the price of RAM per megabyte has decreased by a factor of a hundred million. Similarly, hard drive capacity has increased from tens or hundreds of megabytes to terabytes. It is remarkable that, despite this exponential growth in data storage capacity, the relational model has remained dominant.

Virtually all relational databases are described and queried with variants of SQL (Structured Query Language...