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I do truly appreciate the critique you've offered, as it has some well-thought out objections to the language. I don't want to get into a back and forth on how

by greggyb 11y ago

I do truly appreciate the critique you've offered, as it has some well-thought out objections to the language. I don't want to get into a back and forth on how to deal with the specific issues - they're good food for thought, but I think it wouldn't lead to a productive conversation. I would object that SQL is actually incredibly high level, though its abstractions differ from the typical ones seen in other programming languages. As a declarative query language, I can describe a join between two arbitrary (no need to do anything besides have the tables exist) tables and the query optimizer will do a very good job of choosing among several different algorithms to perform that join for me. Without a thought to any statistics of the data, the query is optimized appropriately, including the construction of a temporary index if that is the best way to compute the join. Or, transactions in general - ACID guarantees are maintained with a simple transaction - almost no boilerplate, just saying where it begins and where it ends with some options for specific behavior, and the transaction is guaranteed on arbitrary data structures without any other code necessary. I won't go into the data consistency guarantees you can make just by defining a couple of foreign keys and constraints (performance aside - these can be optimized - this would be awful to put together by hand in a project) These are some of the abstractions in SQL which are absurdly high level compared to doing something similar in another language. Several of your bullets also support that it is a high level language, e.g. 4 "others may be implementation dependent" - this is not a statement ever made about assembly for example. SQL is, at the end of the day, a query language built around relational algebra, already an abstract topic, and implemented on arbitrary hardware, operating systems, filesystems, and so on. It's not got a lot of high level concepts that exist in other languages, sure, but it's got a lot of stuff built in that would be a bear and a half to implement on your own. Its high level concepts are in general very orthogonal to those in other languages. Again, I'm not disagreeing with your bullets, and I appreciate the time you took to reply and your points are exactly the sort of thing I was asking for. I just think that you're ignoring some of the power in it for want of the power of constructs you're more familiar with.

T-R 11y ago
It's definitely relevant that my complaints are from a Haskell perspective (as this is a Haskell thread). If I'm working in just about any procedural/OOP language, sum types are a completely foreign concept. If I'm working in PHP, I don't expect a consistent API. If I'm working in a strict language, I don't expect to be able to abstract my data model away from how I loop over it in memory. If I'm used to anything without some support for dependent types, I just assume that an empty list, or a list with too many entries couldn't possibly be detected at compile time. The high level constructs it does have are strictly less powerful, largely as a function of not being composable/consistent and certainly not as polymorphic as the kinds of things in Foldable/Traversable, though certainly better than writing your own for-loops. The thing is, these are practically all you do in SQL, so it's pretty frustrating that, when working with it, so much time is dedicated to dealing with these solved problems. They're the reason you can't import a "votes" or "comments" package to your database, and why being a database expert is such a niche, specialized, and lucrative position - because so much knowledge isn't captured in the language, or the compiler, or libraries (even though it quite feasibly could be), but just spread by books and blog articles. It's why building complex things on relational databases is so hard - the level you're working at is strictly limited to "what keys do I join on to get the result set I want" and "how do I make this only loop once" - it's not inherent in the relational model/relational algebra, it's strictly a problem with SQL. To add, as a declarative query language, it's worth also comparing to things like Prolog/Datalog. Prolog certainly doesn't get you all of the things I mentioned, either (e.g., no dependent types), but it is a much higher level of abstraction - you can describe things like "this is a one-to-one relationship" at a high level. The flipside is that, to write performant queries, you need to understand the Warren Abstract Machine, but because of its consistency, that's a significantly lower barrier to entry than trying to understand a specific database's optimizer implementation, or the arbitrary decisions in the SQL spec, and the knowledge there is actually transferrable.

by greggyb 11y ago

T-R 11y ago

It's definitely relevant that my complaints are from a Haskell perspective (as this is a Haskell thread). If I'm working in just about any procedural/OOP language, sum types are a completely foreign concept. If I'm working in PHP, I don't expect a consistent API. If I'm working in a strict language, I don't expect to be able to abstract my data model away from how I loop over it in memory. If I'm used to anything without some support for dependent types, I just assume that an empty list, or a list with too many entries couldn't possibly be detected at compile time. The high level constructs it does have are strictly less powerful, largely as a function of not being composable/consistent and certainly not as polymorphic as the kinds of things in Foldable/Traversable, though certainly better than writing your own for-loops. The thing is, these are practically all you do in SQL, so it's pretty frustrating that, when working with it, so much time is dedicated to dealing with these solved problems. They're the reason you can't import a "votes" or "comments" package to your database, and why being a database expert is such a niche, specialized, and lucrative position - because so much knowledge isn't captured in the language, or the compiler, or libraries (even though it quite feasibly could be), but just spread by books and blog articles. It's why building complex things on relational databases is so hard - the level you're working at is strictly limited to "what keys do I join on to get the result set I want" and "how do I make this only loop once" - it's not inherent in the relational model/relational algebra, it's strictly a problem with SQL. To add, as a declarative query language, it's worth also comparing to things like Prolog/Datalog. Prolog certainly doesn't get you all of the things I mentioned, either (e.g., no dependent types), but it is a much higher level of abstraction - you can describe things like "this is a one-to-one relationship" at a high level. The flipside is that, to write performant queries, you need to understand the Warren Abstract Machine, but because of its consistency, that's a significantly lower barrier to entry than trying to understand a specific database's optimizer implementation, or the arbitrary decisions in the SQL spec, and the knowledge there is actually transferrable.