Slides from my guest lecture for the University of Cambridge undergraduate course in computer science, part of the lecture series on databases. Lecture given on 4 March 2016.
The audience for this lecture was second-year undergraduate students who have learnt about SQL and relational algebra, but who have little practical experience in working with database systems.
My goal in this lecture was to use various examples to illustrate why one might use different data models and different storage technologies in different situations — there is no "one size fits all" database that can handle all possible data management needs. Every data management approach works well in some scenarios, and runs into limitations in other scenarios. These trade-offs help explain why there is such a variety of technologies.