Review: Introduction to Databases — Stanford Class2Go

Jennifer Widom’s Introduction to Databases has an impressive pedigree, having been one of the three inaugural Stanford MOOCs that caused the avalanche of online courses we can all enjoy today. Furthermore, this course has had many homes, tracing part of the MOOC revolution. Originally, it was a stand-alone class offered by Stanford in autumn 2011. The content was later on added to Coursera and offered in self-service mode, i.e. without exam and involvement of TAs in the forums, before it was offered again this January on Stanford’s Class2Go platform. Less than a week ago, though, it was announced that Class2Go would be folded into MIT and Harvard’s EdX platform. On a side note, the other two inaugural Stanford MOOCs were Andrew Ng’s Machine Learning, and Introduction to Artificial Intelligence by Peter Norvig and Sebastian Thrun. Andrew Ng became co-founder of Coursera, and Sebastian Thrun launched Udacity. Looking back, it’s quite amazing how much has happened in the course of little more than a year.

Unlike machine learning or artificial intelligence, knowledge in databases is likely to be relevant for a large part of software engineers since databases are ubiquitous. I think that a course on databases is one of the most “useful” courses one could take as part of a typical computer science degree. Such knowledge is presumably deemed too practical in some departments, which might explain why an intro to databases is often an elective instead of a mandatory course.

I took an introductory database course last semester at university, and frequently referred to some of the videos of Jennifer Widom’s class, which was offered in self-service mode on Coursera back then. I found her explanations very lucid. My lecturers were overly fond of theoretical explanations, without demonstrating how the concept are used in practice. In contrast, Jennifer Widom follows a didactically much more sensible approach by showing examples first and explaining various pros and cons before eventually covering theoretical definitions. Her explanations on referential integrity and the various so-called normal forms were all very clear. She even helped me understand multi-valued dependencies, which I initially found difficult to grasp. However, that kind of knowledge will presumably be less relevant in practice.

I originally didn’t intend to go through the entire course, since I have already taken a similar one at a brick-and-mortar institution, but shortly before the course started, I learnt that Introduction to Databases was moved to Stanford’s new platform Class2Go. I was simply curious how their platform worked and had a look around. What motivated me to work through the material was simply the great amount of flexibility it offered. Even though the content was spread over nine or ten weeks, everything was available from the very beginning. There were deadlines, but you had the option of working well-ahead of schedule. The only other fixed dates were two two-day periods for the mid-term and final exam.

I wasn’t going to invest a lot of time in this course, but wanted to explore areas I hadn’t been exposed to yet, or only cursory, such as JSON, and more advanced SQL topics like views or triggers. I was thus pleased to notice that the course had two different tracks. If you wanted to earn a statement of accomplishment, you had to score 75% from a weighted score of exams, interactive exercises and quizzes, in addition to scoring 75% of so-called challenge-level problems. I was content with the regular statement of completion that was awarded for a score of at least 50%. Thus, I skipped most of the challenge-level exercises. The course itself offers a smörgåsbord of database-related topics. The curriculum even encouraged designing your own learning path, and the conditions for the statement of completion were such that you could easily skip a few topics and still “pass” the course.

I very much enjoyed learning about JSON, which made me even more skeptical about XML. Another highlight was recursion in SQL, but this topic might see little application in the real world. I’ll just list all topics of the curriculum so that you’ll get an idea of the breadth and depth it offered:

– Relational Databases (relational model, querying)
– XML Data
– JSON Data
– Relational Algebra
– SQL (main commands)
– Relational Design Theory
– Querying XML
– SQL: Indexes
– SQL: Transactions
– SQL: Constraints and Triggers
– SQL: Views
– SQL: Authorization
– SQL: Recursion
– SQL: On-Line Analytical Processing

Of course, SQL is the 800 pound gorilla you just won’t get around. However, the supplemental topics were well-selected. This course focussed more on practice than theory, which working professionals might appreciate. Still, you’ll be taught substantial amounts of database theory, meaning that this course is not lacking in that regard either. If you want to thoroughly go through each module, you should plan to invest a good five to eight hours a week.

Overall, Introduction to Databases truck me as well-designed. The quality of the teaching was top-notch, too, with Jennifer Widom taking great care to illustrate every concept, and spending copious amounts of time demonstrating them in practice. The course was surprisingly hands-on, and a significant part of the videos were screencasts showing the instructor querying a database, explaining peculiarities of SQL syntax along the way, or pointing out common mistakes.

The course is currently offered in self-service mode. If you want to learn about databases, it is an excellent starting point. Please note that even though this course does refer to three database textbooks, you won’t have to buy any of them since the teaching materials are of a very good quality. I own a copy of Jeffrey Ullman and Jennifer Widom’s A First Course in Database Systems, which complements this online course. However, it was merely in the “nice to have” category, meaning that I think it’s quite possible to make it through the course without a textbook.

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