Let’s Build a Simple Database (2017)

I have spent quite a lot of time building a database in Java. It's not a small undertaking. I've gone through as many books and papers as I can, and there is only one, one, that gives an overview and actual examples of building a system that processes SQL. Everything else is theoretical or so general that you don't get enough direction to get started. It's "Database Design and Implementation" by Sciore. It's a little dated, but not by much…

A bit shameless to ask a question under top HN record, but I always wondered why do not SQL engines give access to their SQL AST to generate queries. Of course, one can combine a query from strings with placeholders, and it takes not so much comparing to actual querying process, but it feels so hacky. Why not provide something like: Query *q = db_select(db); db_add_from(q, "persons"); db_left_join(q, "companies", db_expr(DB_EQ, "per_id", "com_id")); Query *q = db_create_table(db); db_add_column(q, "id"…

In software, as in most things, most of learning is done by doing. Creating a clone of something from scratch is a really useful learning technique and has the benefit of a defined specification. It doesn't even really matter if the job is even completed or if the program is ever used. The important part is the doing, not the result. I confess we did similar things at uni 30 years ago, although we mostly re-implemented arcade games, not sql…

Discussed at the time: Writing a SQLite clone from scratch in C - https://news.ycombinator.com/item?id=15168467 - Sept 2017 (146 comments)