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I have seen sql queries that were 30 pages long if printed out. The developer showing me this was looking for some other examples that he said were up to 100 pa

I have seen sql queries that were 30 pages long if printed out. The developer showing me this was looking for some other examples that he said were up to 100 pages long. These queries had multiple levels of correlated subqueries and tons of decode statements ( oracle syntax). There looked to be tons of duplication just in what I saw. How are you going to write unit tests for that stuff? Refactor? etc. etc. The examples always start out simple like summing a bunch of rows that match a predicate but once you start doing that it is hard to rewrite that to use application code once it becomes too complex. Also most databases are 20+ year old technologies and often have weird systems in place for storing the code in the db or something else just as odd. No more grep, no more static code analysis. As far as I am concerned the db is a pile of facts or observations. I tell the db something and later it tells me what I told it. When I am thinking about what goes in the db I think about using the past perfect verb tense. On this day such and such happened. Thats it. Preferably that never changes, you might get new info in the future so just record that new info along with everything else. Ideally we should be getting to a point to where resources are so cheap that CRUD can become CR - no more updates or delete just new facts.

ef4 13y ago
The existence of terribly written queries proves nothing. Because there's also plenty of terribly written code that takes 100 pages to do something simple. In both cases it comes down to people blindly grasping when they don't understand the fundamentals. Relational logic can be extremely elegant, composable, and testable. Unfortunately SQL is a pretty awful interface to expose those ideas, and most attempts to wrap SQL in a better interface make the mistake of trying to pretend to be object-oriented, when they should really let their true relational nature shine through.

ef4 13y ago

The existence of terribly written queries proves nothing. Because there's also plenty of terribly written code that takes 100 pages to do something simple. In both cases it comes down to people blindly grasping when they don't understand the fundamentals. Relational logic can be extremely elegant, composable, and testable. Unfortunately SQL is a pretty awful interface to expose those ideas, and most attempts to wrap SQL in a better interface make the mistake of trying to pretend to be object-oriented, when they should really let their true relational nature shine through.