Hypothetically, if I were to use a much simpler database (let’s say SQLite or BerkeleyDB) for a project, rather than a powerful RDBMS like PostgreSQL, what would be the first thing that I would miss from PostgreSQL? Not “miss” in a theoretical, long term sense, but “miss” in that it would cause a practical impediment to actually constructing even a prototype application?
Would it be triggers? Certainly not. Server side functions? Those would certainly be missed, although may projects go along fine without them. SQL’s relational algebra and calculus that make a relational database relational? Maybe, that would certainly be preferable to procedural code using BerkeleyDB, but I don’t think this would be the first thing I’d miss (digression: actually, it wouldn’t be missed until later, when I was actually trying to debug a difficult problem or look at the data for analysis).