“Experts often possess more data than judgement.”
In previous chapters, we implemented all the business logic for the payroll application. That implementation had a class,
PayrollDatabase, that stored all the payroll data in RAM. This worked fine for our purpose at the time. However, it seems obvious that this system will need a more persistent form of data storage. This chapter explains how to provide that persistence by storing the data in a relational database.
The choice of database technology is usually made more for political reasons than for technical reasons. ...