We Can Do Better Than SQL
edgedb.com
edgedb.com
All that said...SQL is pretty darn effective. As a language, it's the true backbone of the internet today. It's readable, explicit, fairly concise and naturally translates to how data should be broken down for efficient storage...or make some trade-offs to allow for more efficient retrieval.
There are differences with different vendor implementations...but that's what different vendors are for - to find things the other guys are doing wrong and improving on them to build a better product.
I wish the folks luck in their work to improve things, but the language I've been able to rely on consistently over the last 17 years or so has been SQL...and I've worked with a lot of languages. SQL is the one that gets the most done reliably and lets me down the least often.
Most of Postgres is standard SQL. It's just that most non-Postgres databases do not implement standard SQL very well.
Sure, but the non-standard enhancements like JSON support are part of what sets Postgres apart from the competition IMO.
In PG, a JSON column is so well integrated that you can do all sorts of crazy stuff (indices over JSON queries is my favorite). You could build an entire RDBMS on top of PG's JSON column.
[1] https://modern-sql.com/slides/ModernSQL-2019-05-08.pdf, for example
(Edited for formatting.)
The release is planned for roughly next September/October.
It's got a lot of stuff going on in there.
This sounds amazing. Does anyone have a link to some docs for this?
Call it a "hint", if you will, the meaning of which is implementation defined. But standardize the syntax for pete's sake.
And "hints" in the language are not exactly going to improve "interoperability" if their meaning is still allowed to be implementation-defined, are they ?
That's correct, and that's why PostgreSQL has ADD CONSTRAINT.
The constraints describe the actual schema of the data; INDEX is an DBMS-specific implementation* for improving performance (including index types, etc.).
* Those since the standard does not yet cover some thing partial unique constraints, these have to be done as INDEX in PostgreSQL.
That's not a bug, that's a feature. Deriving from the deliberate intent to make physical independence (which was simply nonexistent at the time the model was conceived) a reality.
Postgrest works very well as this shim layer, though I've moved on to writing sql directly in the client and communicating through a web socket shim. In terms of reducing code complexity and improving performance this is absolutely unbeatable, you just need to parse incoming sql to sanitize it and make sure there is no role escalation. Because of postgres's foreign data wrappers this method can provide a consistent surface for basically all your enterprise data. The only gotcha with FDWs is that some of them don't "push down" many query clauses, so you end up doing much slower queries on the remote system and filtering locally, which is terrible for obvious reasons. That being said, the FDWs are pretty much all open source, so you can just implement push down support for those missing clauses yourself.
"Just"? I guess I'm skeptical of a statement that begins "you just have to parse sql".
Is this actually easier than I'm imagining it? I'd be curious to hear more about the security and authorization model of this approach.
A good tool for this purpose is https://github.com/JavaScriptor/js-sql-parser as it will fail to parse complex statements that are likely to include an attack vector.
In terms of authorization, you can either create per user connection pools if using web sockets and log the user in directly that way (which makes things easy) or if you must use rest, use a single connection pool with a master user then use some form of token to tell the shim who to set role to before executing the query.
As I learn more about SQL and pull off more complex queries, my respect for it deepens. To have such power and support so many use cases with so few constructs is really an engineering feat. It’s timeless for a reason.
Some of my relatively common access patterns are awkward to express, but they can still be expressed in a few lines + a CTE or two, which is really impressive for a language so small.
This is not to say we can’t do better. But SQL has achieved a deep resonance with its problem space that most tools don’t even come close to. The brightest minds and most effective tooling shops in our field would be lucky merely to do as well.
I mean, if I gave you protons, electrons and neutrons, you could build the universe out of them!
Expressiveness isn't inversely correlated to number of constructs.
In reality, it's not just about the small number of constructs, but also about how fundamental they are. In one sense, atoms are less fundamental than protons/neutrons/electrons, and therefore reduce the number of possible creations.
> In reality, it's not just about the small number of constructs, but also about how fundamental they are. In one sense, atoms are less fundamental than protons/neutrons/electrons, and therefore reduce the number of possible creations.
I think what OJFord is getting at is, what if you had more subatomic particles to build with?
Thus, whatever the complete set is for subatomic particles, it will most certainly have lesser members than for the complete set of atoms.
Getting back to my original point, SQL operates at a fundamental enough level that you do not need a great number of "constructs" to create a query that gives you whatever it is that you need.
I'm not saying it's perfect, but was just supplementing the OPs observation that SQL has surprisingly few "constructs".
Are we just assuming that protons and neutrons automatically pull in the quarks, neutrinos, other leptons and force carriers as well? Does the electron have a photon dependency? What about dark matter?
If not, then the our three particles are internally inconsistent and woefully incapable of building a universe. Otherwise, our set of dependencies is essentially the whole darn universe anyway.
Same goes for atoms. Give me enough and I can build a star or particle accelerator to create whatever elements or fundamental particles I want.
Also, the GPs suggestion of building an accelerator is as silly as someone writing an assembly compiler via a mush of SQL. It probably can be done, but it's not in the spirit of the topic!
Anyway, I feel like your original comment and my reply are kind of doing the same thing at the meta-conversation level. We're stretching a metaphor in order to make some counterpoint argument. My intent with the excessive pedantry was to highlight the farce of conflating rough metaphor with substantive insight.
Anyway, internet conversations are hard. Thanks for engaging!
Radiation makes the universe a lot more interesting.
Given the vast usage of SQL and its overwhelming popularity, if there were real problems with the language then there would be a lot more noise about them. But most people seem to be happy with it.
If it's not broken, let's not fix it, eh?
>Given the vast usage of SQL and its overwhelming popularity, if there were real problems with the language then there would be a lot more noise about them. But most people seem to be happy with it.
In what universe does popularity imply quality? Certainly not the one I’m in — Avengers endgame is apparently #2 gross worldwide ever :-)
Which finally implies that usage popularity is not adequately explained by user preference, because you wouldn’t expect user language preference to have significant impact on the decision making process.
But regardless, are you also going to claim that C, Oracle, IBM, Microsoft, etc were optimal in their respective fields, during their respective eras, because they held total market domination? Incumbency is one hell if a drug..
Bandwaggoning and deffering to the status quo is not argument for quality; there are too many factors involved beyond quality itself. Fixable flaws in the language have been pointed out and not been addressed in this conversation chain. Alternatives languages exist, both academically and practically; they don’t come alone. Its not a competition in a void, the ecosystem has to move together. This occurs in every aspect of tech (did you ever wonder if there could be an OS other than unix and window styles?).
Asking why SQL was never beaten out in popularity is a hugely different question from whether there can be a better language than SQL, with largely unrelated amswers(Oracle/IBM were hardly fair players in anything they did)
The lack of popularity is also a reflection of how the string of next best things have failed to actually deliver on their promise, accompanied by the lack of a rational argument to adopt them instead of using a time-tested technology.
The SQL language is just an API to the total engine; the majority of its value derives from the relational model; the value of the relational algebra is not being questioned. Only the particular interface to describe the relational algebra.
The power of the JVM is not the power of the Java language. You can have other languages make use of the same power Java has access to by targetting the JVM, and as a programming community we accept that just fine (and we also accept that despite Java having many known flaws as a language, its status as a first-party Oracle interface to the JVM, and its position within the status quo, makes it extremely difficult to upend; but that hardly implies Java is some perfect language, as most HN users will trivially acknowledge).
In the same fashion, the SQL language is (ideally) decoupled from the RDBMS engine; it can be replaced. But in practice, they're not so decoupled, and SQL has been consistently the only first-class interface to the engine, so like Java, it (can) enjoys far greater ubiquity and stability from the quality of the underlying tech, than the language itself may deserve.
So once again; popularity/stability of the SQL language is not (necessarily) exemplary of the quality of the SQL language. It's much more likely that it represents the value of the RDBMS, and the relational model (which I don't think anyone is arguing against), and the SQL language enjoys a free ride by being the only interface thats even offered.
I mean hell, just read the article. It has trivially observable flaws in its design and semantics (like stuffing a 3VL logic into a 2VL language). EdgeQL may or may not be the optimal solution, and I'm not arguing (or interested in arguing) one way or the other on that, but I don't see how anyone can reasonably argue that SQL's ubiquity shows its perfection, when it's so clearly imperfect (because those flaws are being very directly pointed out).
Why is SQL the exception to the rule? You talk about popularity, but its really a question about stability. Remember, SQL is not that popular, as the NOSQL movement and comments like yours prove.
I don't think you've picked a very good example here of a field where the lingua franca has progressed over time. C still dominates nearly all systems programming, against all odds. It dominates operating system development, driver development, embedded systems development, pretty much anything that demands an extremely high degree of efficiency.
I agree with your overall point regarding SQL and its superior stability, but C is an example of where popularity won out against many better options over time. It's not like Rust was the first mainstream attempt to create safer languages for systems development either. There's been many over the years designed to fill the same niche, with more modern features, tools and goals. For better or worse, C still dominates the landscape for reasons entirely independent of whether or not it was truly the best tool for the every task.
Also, I'd contend that your claim regarding the popularity of NoSQL is incorrect. If you only talk to web developers writing Javascript, you'd get the impression that NoSQL is taking over the world. But the reality is that amongst pretty much every other demographic, SQL is still highly regarded as the ideal technology.
Well yes, because I argued that it was irrelevant to the original question: can SQL be improved?
Additionally I actually did address the question of SQL’s stability, at least partially: it’s not SQL thats so stable, but the relational model. SQL just happened to be IBM’s, and IBM was highly successful pushing its DB around, and Oracle (kind-of) cloned it to push their DB around with less contention, and so it went on. But its the RDBMS engine that primarily pushes a DB’s value; The SQL language is a ride-along.
And once more to be clear: its longevity is not a result of SQL’s quality, but the quality of the relational model. Thus its popularity, and stability (its also not that stable, in that its heavily extended by everyone in arbitrary fashion), is irrelevant to the original question.
>SQL is not that popular, as the NOSQL movement
If people are trying to make use of NoSQL because they want to avoid the SQL language (not the relational model), they’ve made a grave mistake in understanding their technologies; I don’t think such a naive opinion should be considered relevant to the equation.
If they’ve chosen NoSQL to avoid the relational model, then their choice says nothing about the SQL language.
Yes, they are trying to avoid the relational model by avoiding SQL because SQL has basically been the face of the relational model for 40 years. if there was something better, they'd use that. Nothing better has come up, and i don't know why either.
If you want to believe that popularity is a measure or reliable indicator of quality, I can't be bothered with you.
PS I have a worked-out example on my site of what it takes to enforce a business rule "no one has a salary higher than his manager's" in SQL (> 100 LOC) and in SIRA_PRISE (one single relatively simple formula of the RA to declare). You decide which is "better".
However, there is a more insidious problem with SQL: it's all too easy to write SQL statements that have O(N^2) complexity. A simple JOIN can easily result in O(N^2) complexity, yet there aren't easy tools to identify these performance issues. As a result, as a database grows, things that once were executed quickly take forever.
I'd like to see the end of joins, replaced with something that is more explicit about what is happening under the hood.
However. You are wrong tying the problem to joins. I remember an analyst who launched a SELECT COUNT because he was just curious about the number of rows in the table. No joins involved but users did suffer. Elsewhere in this thread I've seen the problem be tied to table scans, and that's also wrong. A table scan isn't a problem if it's a 5-page table. As Darwen often argued : why are people always only lamenting about those couple of tables with millions of rows ? Why should we deprive users of the power of relational algebra if their database simply aren't that big ?
It's a matter of determining the cost of the data access strategy (regardless of JOIN/EXCEPT/what_have_you) and (implementing a protocol for) capping it at runtime (or earlier if possible). No need for language changes here.
I was using joins as the common example. Sure, there are many other ways of using SQL to shoot yourself in the foot, but most of the issues I've run into seem to come from joins.
I don’t see the relationship between those two things; or rather, what the latter even means. Can you expand?
Also, apparently the “sets” described in the article are actually multisets aka bags [0] — so the same semantics as any other RDBMS/SQL. No idea why they’d confound the two, especially when set vs bag semantics is a well-discussed topic in the literature..
[0] https://edgedb.com/docs/edgeql/overview/#everything-is-a-set
SELECT StudentID, Name, (SELECT COUNT(x) FROM StudentExam WHERE StudentExam.StudentID = Student.StudentID) / (SELECT COUNT(x) FROM StudentEnrollmetnPeriods WHERE StudentEnrollmetnPeriods.StudentID = Student.StudentID) AS ExamsTakenPerYear FROM Student ORDER BY ExamsTaken DESC;
works because the result from aggregate are scalar and thus math operations always meaningful, albeit this in particular might not be the most brilliant example, there's definitely a case for running such operations on the server, because you might filter on the results, say, like
"select all student with less than 2 exam per year average"
at which point either you have the distinction between scalar and set in the language itself and you can filter invalid queries at the parsing level or you have to do the checks at runtime when two set are in an operation with mixed cardinality, halt the query and throw an error.
edit: count(x) because I don't know how to escape asteriks
it's not coincidence that the article complains about the same thing but in reverse:
> This is legal, but only if the subquery returns not more than one row. Otherwise, an error would be raised at run time.
except the 'fix' reintroduce it in a way that's subtler and way hard to detect because now everything is a set even when the intent is to have a scalar.
I'll give you just one : in SQL, you can write "WHERE 4 > (SELECT COUNT() FROM ... WHERE ... )" but you cannot write "WHERE (SELECT COUNT() FROM ... WHERE ... ) < 4" [Darwen, "The askew Wall"].
Or iow, for certain specific kinds of 'a' and 'b', you can write "a < b" but not "b > a". Do you actually know ANY language that exposes that kind of thing ??? REALLY ???
A lot of HiveQL's power comes from extending the language, not from the use of a small set of timeless features.
All that said I think it was originally structured to partially be a human readable language and it fails pretty hard at that - that's a facet I'm sure smart people could revise to make more natural.
More legitimately splunk may simply be unable to deliver performant data expression if a user is typing a query complex enough to justify SQL.
The problem isn't SQL. It's that Splunk's query engine is tied up internally with a "grammar" that is a direct port of a shell pipeline into C++ with no intermediate representation or anything a compiler guy would recognize as a grammar. There was no design, no mathematical underpinning to it.
Splunk's unstructured log capabilities are really domain knowledge about making them semistructured as fast as possible: token indexing, a lot of effort on recognizing character encodings and timestamps intelligently, looking for key=value pairs, and letting people write regexes to extract fields themselves. The query language isn't somehow designed for a different data model.
In EWD1123, Dijkstra showed that the relational calculus and the regularity calculus (which governs regexes) are basically the same thing. My takeaway from that is that the relational model can be reinterpreted as a model over anything you want to match and manipulate with regexes by just changing the field selectors.
As a standardized language, it doesn’t really exist; everyone implements numerous extensions, and almost no one is fully ansi compliant
Almost all formatters attempt to be generic (believing standardization exists), and fail to support the full grammar for any dialect.
Across the board, all parsers have pathetic error message support (error on line 3, which is actually just the start of the statement).
The schema offers type constraints, but querying/ide’s extract no value from that (that is, types are statically specified/constrained, but query editors all pretend its fully dynamic)
Theres a lot of awkward nonsense, like where clauses are parsed before the select in most parsing engines, causing alias usage to fail without wrapping in a subselect/with clause
The grammars themselves are an inconsistent, ad-hoc mess
The grammar is also unnecessarily context-dependent (eg from must follow select, and where after that), making programmatic composition unnecessarily difficult
I don’t know how much of the tooling issue is a result of SQL as a language versus the history itself, but I can at least confirm that trying to parse multiple dialects is absolute hell, which would at least explain the sorry state of affairs for eg formatters.
But the majority of its expressive power derives from the relational algebra, and has nothing to do with the SQL grammar, and thats the majority of its value. It seems obvious to me that at the very least the compositional issue of SQL, and its self-inconsistent grammar, should be vulnerable to near-lossless improvement without too much struggle, though I can’t say what the alternative would actually look like.
But it seems like its riddled with a lot of unnecessary flaws
I was experimenting around with creating an Entity Framework equivalent in Typescript and really wanted to create a SQL AST for use under the hood(optimizing queries, SQL push down, etc). Ended up using the PostgreSQL types and a Ruby plugin that binds some PostgreSQL libs to work on my POC. Crazy town.
But, the common workhorse tool that has stayed strong through all these has been the common SQL. Elegant, simple, powerful and thoroughly reliable, it is my primary go-to tool. In an otherwise changing ecosystem, its simplicity and reliability is a boon. Yes, it is primarily because of the nostalgic familiarity but I also believe it continues to be extremely powerful, one that will serve you very well.
FWIW postgres used to have its own query language derived from QUEL[0] rather than SQL.
And findings that SQL is kinda shit are not exactly recent, e.g. C.J. Date's "A Critique of the SQL Language" (1983) lists the following sections
* lack of orthogonality: expressions
* lack of orthogonality: builtin functions
* lack of orthogonality: miscellaneous items formal definition
* mismatch with host languages
* missing function
* mistakes
* aspects of the relational model not supported
The conclusion was, obviously, prescient:
> if SQL is adopted on a wide scale in its present fortm~ then we will to some degree have missed the relational boat~ or at least failed to capitalize to the fullest possible extent on the potential of the relational model. That would be a pity, because we had an opportunity to do it right, and with a little effort we could have done so. The question is whether it is now too late. I sincerely hope not.
SQL succeeded not because it's "pretty darn effective" but because IBM decided on it (at a time where it drove technology) and Oracle are great at sales and marketing (whereas Ingres definitely wasn't).
Of course we can do better than SQL. We could obviously do better than Javascript. It’s globally understood that we could all do better than English.
We sometimes struggle to express ourselves with language. We can blame the language, try to fix it, or invent a new language and try to get people to speak it.
I would rather spend my time refining my elocution than learn a new language. That said, there are words and phrases that simply work better in other languages. I don’t know a single-word corollary to ‘Simpatico’ in English.
I wish the best to those who would make programming more expressive, and the worst to those who would try to streamline away subtlety.
Performance is quite loosely linked to language, given sufficient abstractions and optimizations. I submit NumPy as an example. We humans have lots of ways to say what we want, and we want lots of different things in myriad ways. As an analyst I often wish for a richer language, some way I could transcend tabular data thinking to find and make associations around real-world state. I’m certainly self-satisfied when my nested subqueries return what I’m expecting, but I may be able to add more value if I had a better way of expressing my questions.
If we can do better than SQL, it ought to bring more people closer to the reality that lies behind the data, and further from the methods used to obtain it. Maybe I don’t have the words for what I’m looking for yet...
"amiable"? "congenial"? "affable"?
Upvote manipulation maybe? Then once it is on the front-page it gets lots of exposure. So the probability to get upvoted becomes higher.
Perhaps YCombinator omitted the downvote button because it can be abused. For example, if there is a story that is bad news for a certain company, that company could organize a downvoting campaign to hide it. But the upvote button can also be manipulated, as you say.
However, which is worse? (A) To write a silly story and have it rightfully downvoted into obscurity, or (B) To write a silly story, have it upvoted into the limelight, but be littered with comments that expose its flaws.
I think that as long as I remember that just because a story is on the front page doesn't mean it's right, then Hacker News has a nicely curated set of moderation rules.
That's how story flagging currently works though, and is significantly more effective
Posts have an upvote button, but no downvote button, so dissenters can only use comments to express disagreement.
I like the fact that SQL has a solid foundation in relational algebra. I see no such foundation for the alternative.
I do like what LINQ did here (being SQLish), which was to put the FROM clauses first. Some SQL variants have WITH clauses that are quite convenient but you end up with:
WITH (...) AS a,
(...) AS b
SELECT
a.a1,
b.b1
FROM a
JOIN b
ON a.a = b.b
Common alternative: SELECT
a.a1,
b.b1
FROM (...) a
JOIN (...) b
ON a.a = b.b
whereas I'd prefer: FROM (...) a
JOIN (...) b
ON a.a = b.b
SELECT
a.a1,
b.b1“Some variants”, including standard SQL since SQL:1999.
Postgres is changing in the next release, BTW: https://www.depesz.com/2019/02/19/waiting-for-postgresql-12-...
Transpile your language to the equivalent SQL, and rely on decades of research and real world experience in things like replication, optimization, locking strategies, high availability, security etc. the things unrelated to the language current SQL databases are really good at.
Enterprises need enterprisey features.
Even if I was convinced EQL was the future I wouldn’t throw out the old stuff. If the old stuff continues working but there is a smooth migration path, I would probably give it a try.
Think of TypeScript vs. JavaScript.
No, but we have a few ideas on how to connect existing databases to EdgeDB.
> Even if I was convinced EQL was the future I wouldn’t throw out the old stuff. If the old stuff continues working but there is a smooth migration path, I would probably give it a try.
Yes, we'll be working on that.
Your 'transpile' handwaving won't fly. You are blindly presuming that the 'SQL equivalent' (a) always exists (it doesn't) and (b) can always be generated by an automated transpiler (it can't).
We have some_table which we want to join to other_table, but we need to map an identifier through mapping_table in order to do it. So we end up with a query like:
SELECT (...) FROM some_table INNER JOIN mapping_table ON (...) INNER JOIN other_table ON (...) ...;
I know for sure when writing this query that the middle join to mapping_table will map every some_table row to exactly one row (no more, no fewer) in mapping_table. The problem is that the query doesn't capture this. The mapping table isn't really named something as obvious as "mapping_table" so someone reading the query has a hard time inferring what the intent was. It totally changes how you mentally parse and think about the query if the result set can be accumulating multiple matching rows from the join, or maybe even losing rows if there are no matches. You have to go bring up your database schema to figure this out.
And, as a fan of static typing, I can't help but cringe at the possibility of someone changing the constraints on the table without realizing that there are queries which implicitly depend on the old ones. SQL offers no resilience to this and will happily change the meaning of your query without a peep of complaint if you drop that constraint from mapping_table.
If there's a fancy way to capture this "mapping" relationship in standard SQL that doesn't just use a dumb inner join, I'd love to know about it. If not, I'd love a query language that supports some annotations that help reading and are either stripped out before sending to the database engine, or are actually checked at runtime.
Your example query joins one some_table row with 1-n rows on mapping table, and another 1-n rows from whatever else is in there to that. If you're expecting a single row in the resulting set per some_table row, it means that you're filtering very hard (which is fine) or that you've a schema problem (which is the actual problem).
When creating views and sprocs, SQL Server lets you mark them as 'schema bound', creating dependencies on the schema objects it uses.
Not sure if something like this exists in Postgres?
The SQL scripting function is a tool run from a desktop, all emulation and such is JAVA based, with the feature to ask the system what the query is doing. The feature called Visual Explain will explode the query into a graphic representation of how the system optimized it to run. It will recommend indexes as needed. This is very good for understanding when table scans are forced, how files actually joined up, and more.
Folks who know more SQL than me: Is there a good way to say "I would rather this query fail than try to scan a table?"
(I understand full well that that is a problem if the company has kicked out the DBA role and handed it over to the individual programmers, but perhaps that is precisely the problem.)
The DBA you were mentioning here, e.g., could first do a query in the EXPLAIN results, and he'll have his "company-wide queries audit" in a matter of seconds.
They can't, if you do perf testing as part of your pre-release testing, which you should do.
If you aren't doing perf testing, you are saying perf isn't an acceptance criteria, so why are you upset that breaking perf doesn't break tests?
// Dear maintainer:
//
// Once you are done trying to 'optimize' this routine,
// and have realized what a terrible mistake that was,
// please increment the following counter as a warning
// to the next guy:
//
// total_hours_wasted_here = 42And as for "waste" : if while learning a better language, they are in addition also learning the relational model, and to think relationally, (their knowledge of both of which will be VERY poor if all they've ever seen is SQL) then there can't have been much time "wasted", can it ?
It's far too embedded throughout the entire industry and as a data analyst, learning EdgeQL vs SQL and then being locked into a new startup database that could disappear in a year doesn't seem like a high probability strategy.
I wish the people all the luck but unfortunately SQL is "good enough", pretty standardized (I can use just about any relational database and get useful data by knowing the basics). The inconsistencies may be mathematically "ugly" but it's not hard to wrap your head around and overcome.
The JS framework churn makes me super appreciative of the stability that SQL brings.
Even if it's still true, "churn" translates to progress. It would be hard to argue complex web application UI development isn't better off now than it was 10 years ago.
I don't have a citation, but a colleague of mine who's working on front-end projects repeatedly complains that today's JS stacks require half a dozen base JS packages, which in turn download dozens if not hundreds of ancillary packages, not to mention requiring a couple of transpilers and a bunch of tooling.
And for what? Well, just to be able to render some text and a couple of buttons.
Nowadays we have whole server projects that take less than 50MB of source code and dependencies to build, while a miserable SPA with a login screen and a couple of menus and buttons requires nearly 400MB of JS.
That's pretty bleak.
There are projects like create-react-app and Parcel which offer very reasonable zero-configuration toolchains.
If you care a lot about runtime dependency weight, there are lightweight libraries like Preact (3kB).
Why is it so hard to imagine something displacing SQL? A simpler, more predictable syntax seems perfectly plausible--it could ship alongside SQL. Do we have StockHolm Syndrome?
The negativity is surprising and at the same time predictable.
Simpler languages have been shipped dozens if not hundreds of times, and they generally tend towards expressing the things they missed or not giving enough functionality for the things they missed.
I am not saying its impossible, but you're going to have to do a lot more than hand waving to justify the reverse position.
Yes you can make some lovecraftian horrors if you really want to, but SQL is one of those things where just a little bit of knowledge goes a long way. If you can understand the basics you can get a lot of work done.
It's a lot like Excel. You can do some really complex confusing stuff in Excel. But you can also teach the basics to non-programmers quite easily, and command of the basic skills will be very empowering. Basic knowledge of Excel, like SQL, gives the user new ways to leverage computers when creating their own solutions to their own problems.
The problem is not reading SQL, but writing it.
It's a lot like Excel. You can do some really complex confusing stuff in Excel […] Basic knowledge of Excel, like SQL, gives the user new ways to leverage computers when creating their own solutions to their own problems.
I can’t speak to your experiences, but I’ve never in my life encountered someone who was not a professional programmer ever even contemplating using SQL for anything let alone creating their own solutions to their own problems. I think it’s safe to assume that the overwhelming majority of people who use SQL, are programmers who most certainly cannot get by with just basic knowledge.
I have. That's only an anecdotal observation, but it seems to me that the existence of Visual Basic and the popularity over the years, combined with the utter disdain for it by "real programmers" is evidence that, more generally, there are a huge number of kinda, sorta, programmers who are outside the IT culture.
>I think it’s safe to assume that the overwhelming majority of people who use SQL, are programmers who most certainly cannot get by with just basic knowledge.
Most demonstrably do though, so there's that. If you cast a wide net when polling programmers, I think you'd find that mode level of knowledge was relatively low. You don't need to be a SQL rockstar ninja dude to do what most professional programmers are doing with SQL most of the time. Obviously advanced knowledge is good for any professional programmer to have, but the fact is there are a TON of people out there who only know the basics, and that works for them.
After some time, most can handle enough SQL to help customers with basic issues that cannot be handled in the application. Some have become quite good at it, and can do quite non-trivial stuff. None of these folks write any code beyond SQL.
I agree. At the same time a little bit of knowledge is incredibly dangerous.
That query, which worked so brilliantly on the test system during devlopment, suddenly grinds all of production to a halt.
The basic problem is that indexing and other physical performance boosters were not really rerquired when those queries were tested with 3'000 customers.
Being set-based that's quite different when you suddenly deal with 30'000'000 customers and a number of joins, which may not be supported by indexes, since that was never obvious in development.
That said: I'm not arguing against SQL. It's a great language for its purpose. What I do argue for is to have an SQL domain expert and an expert on how it phyisically maps to the underlying database engine for more complex projects.
Such a resource can be immensly valuable in assisting application developers to avoid major mistakes when they deal with the underlying database.
Edit: A couple of issues, which actually negated my argument upon reread
Interesting for you to say that. The last time I went looking for mouse traps, I found that every place I went had a reinvented type, and traditional style were extremely hard to find. Yet, it is true that the traditional style is simple and effective. I've learned from experience that anything else is likely to be useless.
Yes, it was that, but, still, there's a big and growing hurdle here that many similar efforts, with similar objective merits compared to contemporary SQL implementations, have failed to overcome, and not a lot of reason provided to think EdgeDB is better positioned.
> Why is it so hard to imagine something displacing SQL?
Because systems providing just as good solutions to largely the same set of SQL deficiencies have been produced and failed to displace SQL for a couple of decades.
The problem isn't doing better than SQL. It's doing enough better than SQL to overcome the depth of knowledge, experience, support, tooling maturity, and comfort people have with SQL. And that most gets deeper over time, on top of SQL getting internal mitigations, if not actual solutions, to some of the problems over time.
That said—as I’ve done with several before—I’ll probably download EdgeDB and try to do some stuff with it.
There's no reason the industry can't move to new technology for new projects. No one is going to rewrite legacy applications in the new language, at least not until the transition is so far along that SQL specialists are aged out and costly. But for new things? It's totally acceptable to pick new languages.
And btw, this has already happened in some areas. Most developers I know don't code in SQL: they use an ORM provided by their language runtime or a support library. That's essentially the same thing.
This works well enough until your ORM shits the bed and you're forced to figure out why your SQL database is "slow".
SQL isn't slow, ORMs are just terrible when you hit an edge-case or when pretend there isn't a relational model behind your opaque materialised objects.
I used to be one of those developers you mentioned, but I'm not anymore after years of debugging "SQL performance issues" (hint: it was the ORM), and actually taking the time to learn the language and take advantage of specific RDBMS features. My preference has shifted to just use a lightweight library to materialise objects (like Dapper), and write the queries myself.
I know I'm staying with the nulls. I wish the best luck for them, and if it survives to maturity, I'll haply go get the ~1% (probably less) more productivity they offer. But right now I'm not moving. It's sad, really, but things are stacked against them. Change is costly, so we lose all the small changes that could compose into something huge.
The crux is : it takes much much more to achieve that than what the average C# or java coder yup has to offer. So the average C# or java coder yup will dismiss those things too.
There are just so many free things you get with SQL and established RDBMS that deeply impact application features, quality, stability, operations, and much, much, more. I've had to write a custom mongo-db like interface for querying, as well as a fair number of hacky bits to effectively cover the surface area of SQL in an inferior way.
I've learned tremendously, but I just wish people don't follow in my exact footsteps because that's probably wasted time.
That is, a reliable tool that translates 99% of normal SQL into readable Edge SQL, and vice versa, would help adoption a lot.
Remember how new JavaScript features became mainstream though transpiling, long before native implementations.
Perhaps SQL is fine if it's your interface for accessing data on a one-off basis, but if you're trying to build a complex tool on top of it (say, an analysis tool for arbitrary data), the inconsistencies and performance concerns mount. People often end up inventing their own proprietary databases to do these analyses (e.g., virtually any business intelligence tool) assuming they can afford to do so. Perhaps EdgeQL isn't the ideal alternative, but as it is SQL is not good enough for many use cases.
I'd recommend reading the PGSQL manual, they go very in depth about many of the supported features and how they are implement and can be used.
That's kind of orthogonal to what I think is the issue being expressed here.
SQL can do many things; the problems tend to be when a query doesn't perform consistently and predictably. There's always a balance to be struck between communicating what is to be done, and how it is to be done, and SQL leaves so much of the "how" out that the query interpreter/optimizer is incredibly sophisticated and does a fantastic amount of work and yet frequently gets things spectacularly wrong, maybe due to misconfiguration and maybe due to fundamental limitations.
Obviously more information on how to do something is not always better; otherwise we'd be using assembler. But there is a balance.
Experts tend to say "write everything in one query, and if it doesn't work, fix the configuration of your database" which is not helpful given the division of responsibilities in any company. But they will say that because they are devoted to the idea that all that expressiveness is good for something.
If that were true, people would build RDBMS’s in SQL.
It fulfils its purpose and does it well.
Sounds like you're looking for a magic silver bullet - there's no free lunch in our field though.
Lastly, the comment I was replying to can be paraphrased as "well is SQL is so great why aren't RDBMS' built using SQL, huh?". Which is a ridiculous question since SQL isn't the right tool for that job - its very name tells you that.
If you want to continue arguing against strawmen do it with someone else.
Since the addition of SQL/PSM (1996 IIRC) it has become a computationally complete language (procedural like many of the others) with variables and loops and what have you.
There's plenty of brilliant people out there, but when you're talking about replacing the most successful data storage language in the history of mankind, you need everything. SQL has been "killed" many times, everyone wants to sell something. It would probably take involvement from a FAAMG entity. I think the first clue that there's no real room for technical innovation and we're staring at only the opportunity for technical churn, is that no FAAMG players, who definitely operate at-scale, have tried to displace SQL outright already.
TypeScript or Kotlin are really the closest, best and most recent examples of what would need to happen. For me as an end-user, ubiquity and skill-reusability matters. If you don't like SQL, there are ORMs.
It'll take several unicorns and Fortune 100s hiring thousands of engineers to code in an SQL-alternative to create an ecosystem large enough to eventually overtake SQL.
I see that you’ve built this as a patched version of Postgres, but I’m curious how much of this syntax you could implement as a client library and shell that would run against an existing Postgres instance.
Right away, you would get adoption from people who have an existing Postgres, or who want to take advantage of SaaS offerings like AWS Aurora.
Longer term, I could imagine the client/shell being extended to support multiple backend DB dialects, even things like Spark or Redshift which you’d have a hard time modifying intrusively.
It could also be cool to explore interoperation with existing schemas written in plain SQL, so people could adopt it incrementally that way.
> It could also be cool to explore interoperation with existing schemas written in plain SQL, so people could adopt it incrementally that way.
Yes, this will happen too.
> SELECT * FROM table
and
> SELECT count(*) FROM table
This is actually not true, as both return table values. It then says that, in EdgeQL, every expression results in a 'set'. This is a distinction without a difference.
I don't disagree we can do better, but this is the same.
This is a valid expression:
SELECT (SELECT count(*) FROM table) + 1
This is not: SELECT (SELECT * FROM table), 1
In EdgeQL: SELECT (count(SomeType) + 1)
and SELECT (SomeType, 1)
are equally valid. SELECT count(*) + 1 FROM table
And SELECT *, 1 FROM table
Both of which are valid in SQL. And you'd get the same result as in the EdgeQL examples.Indeed, a more relevant second counter example would be:
SELECT (SELECT * FROM table) + 1
Not valid... unless `table` only had one row and one column containing a number.Some people use a thing x
A subset of those people use a subset of x called y
This subset of people have built a tool to make y easier to express
Thus x is invalid
I think that's a really bad argument, if everyone was using ORMs then we'd all merrily forget about SQL and just use ORMs which would become the new "language for structuring queries", but we don't all, and EdgeDB in particular thinks that ORMs provide a much degraded expression set from SQL and thus want to tweak X so that it's as expressible as the tool to express Y but without making it just about Y... I think your goal boils down to shifting the trade-off point between X and Y - the extreme of which is writing a very expressive Y that also supports X but in a non-expressive manner.
SELECT Table1, 1
returns each row of Table1 along with 1 and that 1 returns the set {1} means that you have arbitrarily assigned each row of Table1 a row from the set {1}. This gives what you want in the case of a scalar, but what about a non-scalar.
For example, suppose Table1 contains (John, Smith), (Alice, Perkins), (Bob, Best). Then, what should
SELECT Table1, {1,2}
return? If you do not say cross product, you have arbitrarily assigned rows to one another, resulting in meaningless data. If you say cross product, then you have rewritten the sql expression
SELECT * FROM Table1, (VALUES (1), (2))
I don't disagree the SQL syntax is longer and has some unnecessary keywords, but unlike EdgeQL, the query means something particular.
edgedb> SELECT {'First', 'Second'} ++ '!';
{'First!', 'Second!'}
EdgeQL queries are essentially set comprehensions.SELECT 1
and SELECT * FROM TABLE1 and SELECT 1 compose to
> SELECT * FROM TABLE1, (SELECT 1)
Aside from the different syntax, it is the same kind of composition. Not sure what EdgeQL has gained here, then.
This cannot be the case if you call each thing a 'set'. Unless `(a, b)` calculates the cross product, there is no meaningful non-arbitrary way to assign each element of a to an element of b. That would depend on an ordering, which makes it not a set to everyone but a marketing dept somewhere.
SELECT count(star) FROM table
and
SELECT star FROM table
Are both valid, not equivalent.
Furthermore, listing any kind of set depends on some ordering, be it random.
What would you expect to returned for by this query?
The difference in EdgeDB isn't really everything returns a set, but seems instead to be that everything consumes sets and not just scalars.
I think many here miss totally the point. Is the same mindset that lead to believe C, bash or unix are good(?) then why bother?
I'm very lucky that I start with FoxPro, so I know what is to live with a MUCH better thing than SQL.
To the point:
- "SQL is standard, everywhere... why try to change or do something else?"
I hope none here work in new software products.
And also, try to replace ALL the OLD with the NEW is no the point, is to try to DO BETTER THAN THE OLD.
I suspect most of use are in that business... right?
- "SQL is a good language!"
Superficially, yes.. as good is javascript or C. More exactly to be the "default" option we are VERY lucky SQL is not alike C or JS. But "good" is not. Is adecuate.
IF you DON'T KNOW WHY then learn the why first. For us that LIVE in the RDBMS world is clear as water than SQL is not the ideal, is what we have.
----
Is important to understand that "SQL", Rdbms and the relational model are badly misunderstood (just look how the NoSql movement market itself!)
- SQL IS NOT THE RELATIONAL MODEL, is BASED on it.
The relational model is MORE expressive, powerful, flexible and EASIER than SQL.
- SQL IS NOT RDBMS
A much better APIs can be build on top a RDBMS but SQL is a poor language for that. This is part of why exist so many extensions.
Think, for example, why you can't do
SELECT key FROM BTreeInde_CustomerCode
GROUP BY (whatever -- And I mean GROUP, not SUMMARIZE!)
let city = SELECT name
let filter = WHERE id = @id
let query = city + filter(id=1)
and many many other things like thatMany things that get mixed with the "SQL" language are part of the implementation or capabilities of the RDBMS.
- However, SQL IS A FINE EXAMPLE IN HOW DO DATA
And in fact, is not that hard to imagine a much better version, SQL is not that far from a better option!
I’m not quite understanding the benefit of your example. I don’t personally want to write that style of syntax.
I don't believe it, is insufficient, as a fact.
Compare
let city = SELECT name
let filter = WHERE id = @id
to let city = map name
let filter = filter(id = id)
let query = city |> filter
this is to show that SQL, despite being a programming language, can't compose well.The syntax is not the point.
You can build full apps in forth or lisp (as examples of even more minimal Langs than SQL) but now consider the idea of build a full app in SQL. Without other language making the rest of their limitations.
SQL wasn’t designed nor ever meant to be able to write a full app. You’re expecting it to do something it wasn’t designed to do. Because it is a programming language doesn’t necessarily mean it ought to be able to solve any kind of problem.
I personally don’t think SQL is all that great, for various reasons (lack of standardization with various dialects and their own gaps or abilities).
"We Can Do Better Than SQL"
And the fact that some can't imagine to build a full app in SQL (not as is TODAY but as could BE) is sad.
I live in that world before. With the base/foxpro familia's you can totally build a full app with a database language, in fact, easier than with python.
---
The point here is that obviously, SQL is not mean for programming, but do one-off queries here and there. But it not exist a reason to aim higher.
BTW, part of the laments of the creators of the relational model is that SQL have ruined, like COBOL, the mind of millions of developers.
You are outlining some general purpose programming language that allows querying, information retrieval, maybe declaratively or functionally or using objects? I don’t know - you provide no other details.
How expressive would this language be? What abstractions would it provide out of the box? How expressive is it? Your examples allow some code reuse via naming/aliasing specific clauses... is that it?
Specifically what apps would it allow someone to build? And what trade offs result from those decisions? Is it better suited for mathematical operations or data science vs building general enterprise applications? There’s a difference. Is it interpreted like SQL? Would it need to be compiled?
You’re doing a lot of handwaving, and when pressed for details, you respond with a thinly veiled insult - the problem is with the reader or me specifically for not being able to read you mind. We should take you at face value without question.
Good luck with that attitude in your career.
Yes. That is the mindset in see how "Do Better Than SQL".
> How expressive would this language be?....
As expressive as any other. By coincidence I'm building a relational lang as side project but my post was more about think in how SQL limitations can be lifted.
If all is just "sql is only for data retrieval" then is not much else to add than just spice the syntax, maybe.
> You’re doing a lot of handwaving, and when pressed for details, you respond with a thinly veiled insult
That is not my intention. When I said "Some can’t imagine to build a full app in SQL is sad" I mean in general. I think that that will sound bonkers as say "build an app with xml" or similar. But the point of this post is about how be beyond what sql is.
----
A bit more details, now that you ask for more. My idea is revive the spirit of the dbase family of languages. There, you don't need ORMs, build a database app is alike build any other and the language was powerful enough to not need any else for the majority of their users.
The main abstraction is the "relation" that look at data not as scalar or simply lists, but as SCHEMA + DATA:
city = [name:str, state:str; "Miami", "Fl"]
schema data
and ALL the values are relations: 1 //is alike [value:i32; 1]
Is similar to kdb+:http://www.timestored.com/kdb-guides/kdb-database-intro
and allow to work in vectorized form as in arrays languages:
1 + 1 = 2 //internally: [1] + [1] = [2]
[1, 2, 3] + 1 = [2, 3, 4]
but where arrays languages only have 1 "column" of data, relations are 2d.The next power is add the relational operators:
https://en.wikipedia.org/wiki/Relational_algebra
And because all values are relations, everything can be "queried":
[1, 2, 3] ?where #value == 1 //show [1]
[1, 2, 3] ?union 4 ?join city.id ?sort #name
for i in File.open("...") ?where empty(#line) == false do
etc. Is like LINQ? Yes. Where it differ from "just use LINQ, duh!" is that almost all languages are "scalar is first class, but collections not". Instead the relational model operate on sets/collections and all can be generalized for 0, 1 or many values.All of this is without talking about storage. Is just a regular language with regular stuff. In my case I'm working in an interpreter, inmutable first, structural types. made in rust:
and my plan is use it for replace (embed) a lot of code made in several languages I have around and do data processing logic.
I wish to make it bigger, but that are my plans for now.
My case is for enterprise apps, because that is what I do more. But I don't see any reason to expand it. Implementation <> Language.
Optimally, you'll want to build your full app in a single language, frontend, data queries, everything. That eliminates every problematic interface where you have to re-encode values, verify types and other invariants, connect different runtimes, abstract foreign behavior, etc. (Somehow the JS developers talking about isoiconicity only cite code reuse... And the Lisp ones focus on metaprograming.)
We have a variety of good application languages, so it's a safe bet that one can create a not horrible one; we also have a few standards for IPC and some very safe literature on how to integrate them with a language. Foreign interfaces are always iffy, but it's also settle how to create a not horrible one. The most risky part is data querying, so it makes sense to start with a proven implementation here.
It may help to expand on your proposal. For example, what do you mean with group by, but not summarize? The group by clause says nothing about how to combine data not in the group. That has to be on the select. And I have yet to find a solution that beats ROLLUP for giving a great overview of data.
About the only thing that sucks on the current syntax is that it is not possible to get auto complete in the select, without having some from.
ROLLUP is not the same than groups. With
[1:a 1:b 2:a]
Group by (as is normaly in other langs): [1:[a,b] 2:[a]]
Sql "group by" instead is for summary/tally of data: [1:2 2:1] //assuming count
ROLLUP is for make a nice report! [1:[a,b] Count:2; 2:[a] Count:1]
What SQL lacks (in this case), but the relational model not, is the ability to nest relations as easily as JSON.----
Part of the deceptive power of SQL is that is very adequate and for "just query" of data is ok for most cases.
But as "programming language" it lacks some extra power and versatility.
SQL has nested relations since SQL:2003[1] (called multisets). They are not widley supported and frankly speaking I don't like them.
JSON was finally added with SQL:2016[2].
[1] https://sigmodrecord.org/publications/sigmodRecord/0403/E.Ji...
[2] https://modern-sql.com/blog/2017-06/whats-new-in-sql-2016#js...
And group by does work the same as other languages. However, you can't talk of the group by without the select. So, if you use count, or sum, or max, or ..., Yes it will be a summary. You can use string_agg or friends if you want all values. But... Probably safer to get each as a row.
SQL is a programming language. Is just too limited and that is why many can't imagine to use it for a full project.
But that limitations have no sense. The amount of code, time and efficiency that bring is huge (I know, I code in that kind of lang before) and is discussed in:
http://blogs.tedneward.com/post/the-vietnam-of-computer-scie...
In special look a point 5/6 of Summary. The irony is that we already have a "solution"(sql) to the whole problem, but is too limited and awkward to be used in practique.
What gets me, is even in languages where I'm not working with a relational database, the API for selecting data almost always drifts to something akin to SQL. To the point that I cringe if someone tries to force a new API.
I advocate: Building a relational data model on top of hash-map to achieve a combination of NoSQL and RMDB advantages. This is actually a reverse implementation of posgtresql.
[Clojure is a functional programming language based on relational database theory](https://github.com/linpengcheng/PurefunctionPipelineDataflow...)
[Everything is RMDB](https://github.com/linpengcheng/PurefunctionPipelineDataflow...)
[Implement relational data model and programming based on hash-map (NoSQL)](https://github.com/linpengcheng/PurefunctionPipelineDataflow...)
let keys = SELECT key FROM BTreeIndex_CustomerCode;
let city = SELECT name;
let groups = GROUP BY (whatever -- And I mean GROUP, not SUMMARIZE!);
let filter = WHERE id = @id;
let query = city + filter(id=1);
for city in query GROUP BY keys
....For us who didn't use FoxPro, why was it MUCH better than SQL?
I have the same concerns about the proposed language. Yes it's better, but is that enough? What's going to drive adoption?
I'm a "full stack" developer/speaker, and for a long time I useed English on the front-end, German on the back-end, and Spanish for talking to the databaste. When I switched to English on the back-end I saw an productivity boost and I got better at and started to like English more. But I still talk Spanish with the database. I could probably be more efficient using English to talk to everything. I would probably still use French for design though.
Let's get the history in place first. The relational calculus set up a set of operators. That's what Codd worked with. It was combined with a natural language project at IBM which gave us the vaguely English like syntax of SQL.
> In EdgeDB, the data schema is formulated in a way that is much closer to the contemporary application data model. ...Unlike SQL, EdgeQL can easily extract arbitrary data trees.
This is a reinvention of the the hierarchical database, one of the architectures that was abandoned when the relational database came along. This was all fought out on a large scale in the 1980's.
The fundamental idea that you have a highly structured data tree is what the relational model threw away. "Data Oriented Design"[^1] does a pretty good job of explaining why, but roughly: we're accustomed to programming where we have an object/entity/value that represents a conceptual "thing" in our discourse. We compose things into other things, subtype things, and otherwise deal in things. And this turns out to be a disaster when lots of people need to extend and reuse hunks of the same database. If you give up on things as first class parts of your data model, and only talk about relations among attributes, a lot of those problems go away.
If you want to improve SQL, look at going back to the relational calculus without the natural language veneer. There have been a number of systems that tried that, though none have gotten real world traction. I'm also blanking on their names at the moment, so if someone who's memory is working better can help me, I would appreciate it.
It's not. Just because data can be fetched as a set of "tree-like" things does not make the model hierarchical in any way. But it makes lots of practical use cases easier.
> The fundamental idea that you have a highly structured data tree is what the relational model threw away.
And then ORMs came and reinstated the status quo. Truth is, many applications actually benefit from a highly structured data graph. That said, you don't have to use the "highly structured" bits of EdgeDB, it's perfectly fine if all your types are simple tuples.
> We compose things into other things, subtype things, and otherwise deal in things. And this turns out to be a disaster when lots of people need to extend and reuse hunks of the same database.
I would be very interested in reading about this. Do you have any references? Most cases of "disaster" in my experience had to do with extremely poorly defined and documented schemas that had barely any relation to the actual business model.
type Movie {
property director -> str
};
type Book {
property author -> str
};
type User {
multi link favorites -> Movie | Book
};
SELECT User {
favorites: {
[IS Movie].director,
[IS Book].author,
}
};Would this query result in, e.g. [(director: Null, author: J.K Rowling), (director: Spielberg, Null), ...] or would it be [author: J.K. Rowling, director: Spielberg, ...] or just plain strings: [J.K. Rowling, Spielberg, ...]? I still don't totally get the model here.
You can also query the actual object type by referring to the __type__ link:
SELECT User {
favorites: {
__type__,
[IS Movie].director,
[IS Book].author,
}
};I wonder if there is room for a "TypeScript" of SQL that would allow developers to opt-in to whatever new language features or paradigms we feel SQL is missing.
It would then transpile down to regular SQL to be executed.
This isn't just replacing SQL, they're trying to implement a new data model that is backed by Postgres.
C compiles to assembly or machine code, and TypeScript compiles to JavaScript, and in both cases you have the full power of the level you're targeting, so it's fine. An RDBMS has very specific fast-paths that you really need to hit, or the whole exercise becomes pointless. It's like trying to write a 3D game in JavaScript without any way to access the GPU or even SIMD ops. We can do 3D games in JS today, but that's really only feasible because the browser vendors went and exposed the basic fast paths.
- A tool which transpiles their new language into (multiple versions of) SQLite, MySQL, PostgreSQL - This tool should always produce a correct result (Modernizr) or a specific error (e.g. upgrade MySQL to XX+ to use `NEW_LANGUAGE_CODE_SNIPPET` JSON functions) - A separate tool that up-piles SQLite, MySQL, PostgreSQL to the new language, possibly exploiting new streamlined expressions - An editor with IntelliSense for the new language
Even then you can probably achieve a lot value just by inputting table joins before the developer starts editing code.
---
If you're not doing that then you are just keyword spamming by mentioning SQL.
Ah, I can already tell I'm not going to like this article.
>lack of proper orthogonality — SQL is hard to compose;
Their reasoning: "The difference in structure is large enough to make any sort of source-level query reuse impractical."
This is blatantly false. The second example in the article using the join covers both the single-row and multi-row result cases. Additionally, SQL can be made very reusable and modular using tools like DBT, or within a DB using views or other constructs.
>lack of compactness — SQL is a large language;
It's certainly smaller in the keyword set than almost any other computer language I have used. This is like saying "It's a very cold day in the Sahara desert" when the temperature is 40C/105F.
>lack of consistency — SQL is inconsistent in syntax and semantics;
Is it? Or do people take liberties with their implementations? There is an SQL Standard and Postgres is compliant to it. Other databases not being fully ANSI SQL compliant is the fault of the DB creators, not the fault of SQL.
>poor system cohesion — SQL does not integrate well enough with application languages and protocols.
It is a relational language designed to be used within a relational database. Do the authors also complain that their screwdrivers are very inefficient at cutting meat?
They're onto something with the trickiness of NULL, but there have already been tons and tons of discussions on Hacker News - anyone with database experience, either analytical or transaction, will tell you that imagining a NULL-free world actually creates more problems then it solves.
I found this to be a highly misinformed article, personally; really it's a marketing ploy for their proprietary language. Just like most other "we have our own query language better than SQL" product, it probably isn't.
https://docs.getdbt.com/docs#section-what-makes-dbt-so-power...
One pain point is the integration of non-SQL (e.g. Python) jobs into the flow. DBT only manages SQL scripts, so you can lose some of the elegance when you have to glue some external jobs to it. That being said, the development is pretty rapid and as I mentioned the support is great, so I'm excited to see where they go.
Which is precisely why "better" is both possible and desirable.
And which is also why either of forward and backward "compatibility", to the fullest 100% extent, is intrinsically and inherently impossible.
I can't write a program that works against 'any database', because switching databases means a lot of extra custom work. That means databases can't easily compete against each other. (Oracle's license terms sure don't help.) That's terrible. It's worse than x86/PPC/ARM -- at least with CPUs, a compiler can generate machine code for any of them, coming from the same source code.
We mentioned that there are "many SQLs" in this blog post, but not in this specific context.
> It's worse than x86/PPC/ARM
You're... saying that there should only be one CPU architecture too?
Market forces naturally explain what we have today, therefore ... I'm Don Quixote. Sure, I'll accept the title. Likewise, I could say: if you don't like reading complaints like this, blog posts and internet comments might not be for you. :-)
> You're... saying that there should only be one CPU architecture too?
No. I'm saying that the analogous situation with CPU architectures was observed 50 years ago, and despite causing inefficiencies (especially at first), we've spent the effort to create abstractions to gradually make it easier to describe systems at a higher level. It generally doesn't matter, to either users or developers, that there are multiple CPU architectures. We still have many programming languages, too.
Databases have gone in the opposite direction: while adding features over the years, even when these features are 99.9% functionally identical between vendors, they've picked different syntax and data types. Even though they all speak "SQL", databases are more incompatible today than ever.
I guess what I'm getting at is: it's a good thing that compilers were invented before all software needed an ROI, and it's a shame databases didn't get the same treatment before corporate interests took over.
I am waiting for someone to write a paper titled "SQL NULL is (nearly) a Monad." It is "contagious" just like mapping over None. Sometimes I think it'd be cool to add Maybe<T> columns to Postgres, where operators would do the right thing for Some(x) vs None, but then I think, "Wait, that's how it already works!" At least it is very close. But one way or another I would love to see a re-assessment of SQL NULL from the perspective of category theory. If we could redo NULLs as Maybe types, what would that improve? Incidentally, Leonid Lybkin published a really cool paper in 2014 about handling NULLs with category-theory ideas, but it is more about drawing inferences from incomplete premises ("Incomplete data: what went wrong and how to fix it"). Maybe he'll write something about Maybe column types too. :-)
Also if you are interested in improving relational databases, Codd's 1979 paper "Extending the Database Relational Model to Capture More Meaning" is super interesting. The first part is where he adds NULLs (in order to add OUTER JOINs basically), but the second part is almost never mentioned and gives a way to query the schema itself as part of a database query. It looks a lot like doing graph database queries from your relational db. Also a better kind of EAV pattern. Also more support for OO-style inheritance. Somehow 40 years later it is still way more advanced than any existing RDBMS. It would totally break the parse-plan-execute pipeline of today's systems, but it is fascinating to think about. I wish more people would read this paper before trying to go "beyond relational"!
SELECT null AND true;
SELECT bool_and(column1) FROM (VALUES (null::bool),(true)) AS foo;
In PostgreSQL the first query produces NULL, while the second produces TRUE. Yet, it's also possible to get NULL as a result of aggregating values with bool_and: SELECT bool_and(column1) FROM (VALUES (null::bool),(null::bool)) AS foo;
And that's not how a 3-valued logic works.There are many things happening below SQL layer (storage engines, implementations, hardware etc) as well as above it (applications, reporting engines, various services and whatnot). There are many things happening below IP layer (hardware, protocols) as well as above it (TCP, applications).
Even though there are better ways to build a neck of an hourglass, my bet is that (1) they are not much better and (2) it would be extremely difficult to get them replaced in all the existing hourglasses without breaking things terribly.
Conclusion: SQL is going to stay forever, like it or not.
The problem is getting a replacement on enough databases (storage engines?) so it’s universal. And performant. I’m not sure what’s involved with that but since there are a lot of open source dbs it seems possible.
Nice work
Unfortunately, SQL is good enough for the majority of users and uses.
Doing better is certainly possible, but SQL is much better than a lot of people give it credit for.
> SELECT name FROM emp WHERE role = 'dept head' AND deptno = dept.no
...should in my opinion definitely return only 1 row for each department - from a logical point of view returning multiple rows would mean that the data is corrupt upstream or that the organization itself is corrupt or that there is a lack of attributes in the DB (if no additional selection criteria like for example "management" or "operations" or "deputee" etc... can be added to the query - meaning that no sub/organization can have more than 1 person responsible for the exact same thing).
I admit that this is a very focused critic and that I'm very happy with the current behaviour of the generic SQL language and its special cases which are linked to the DB being used (using currently Oracle, MariaDB, Clickhouse - used DB2, Kudu through Cloudera stack, PostgreSQL, maybe something else) and how it stores/processes the data etc... .
Why not bottom, or are containers not covariant? I'm worried that we're not clear about the difference between variables and values.
> Strictly speaking, EdgeQL sets are multisets [1]
Like nulls, this is another broken aspects of SQL.
Maybe you can address these concerns, but I'm skeptical that it's relational:
* It conflates types with relation variables
* It's using links rather than foreign key constraints
* It doesn't seem like the user can even specify a candidate key
* Which is why the "id" field is magical and special
* Constraints only seem to apply to scalars
The reason SQL has been successful is that tables are dead simple to understand, and you're throwing that out. This feels more like a graph database.
[1]: https://edgedb.com/docs/edgeql/overview#type-system [2]: https://edgedb.com/docs/edgeql/expressions/overview#set-cons...
Yes, `{}` is inferred as `anytype`, but we chose to restrict its use in output for interoperability reasons: the output of a query must be of a concrete, known type.
>> Strictly speaking, EdgeQL sets are multisets [1] > Like nulls, this is another broken aspects of SQL.
From the purity standpoint, yes, but in practice, duplicate values are either expected, or too expensive to eliminate. That said there is a `DISTINCT` [1] aggregate.
> * It conflates types with relation variables
Not exactly. We do use the same symbol to denote a type, and a relation that it represents, but the context of which is which is always clear (i.e. Foo in a cast expression is always a type), but Foo in a regular expression is always a relvar.
> * It's using links rather than foreign key constraints
Links are an abstraction over a foreign key. In the vast majority of cases foreign keys are implemented as 'some_id' -> 'id' anyway. If you want a custom foreign key, you can set an expression constraint on a property or a link.
> * It doesn't seem like the user can even specify a candidate key
type Foo { constraint exclusive on ((.name, .last_name)) }
> * Which is why the "id" field is magical and special
See RM proscription 15 in the Third Manifesto [2]
> * Constraints only seem to apply to scalars
They aren't, see above.
[1] https://edgedb.com/docs/edgeql/funcops/set#operator::DISTINC... [2] https://www.dcs.warwick.ac.uk/~hugh/TTM/DTATRM.pdf
No you can't. Many companies have tried, including very large and successful companies and have failed miserably. Just try out the JSON query language used by MongoDB, including their aggregation pipelines, and you will absolutely love SQL.
Fundamentally, SQL is a declarative language for databases, that makes the easy stuff easy, and the hard stuff doable.
If people want to build new front ends for SQL databases, to make it easier to build apps, I can buy that.
But trying to replace SQL as the standard declarative language for data is a fool's errand. You'd have better luck getting developers to switch away from git. People don't use SQL databases because they're fun for developers to hack on, they use them because they solve a business need.
If you want to innovate in the database space, I think you need to provide something that benefits end users (global availability, auto scaling, speed, client syncing ala Firebase, ...).
I like SQL, but I disagree. It also makes easy stuff hard.
Given many numbers (billions), how would you find the 1st, 3rd and 5th highest values?
SELECT
nth_value(num, 1) OVER ORDER BY num,
nth_value(num, 3) OVER ORDER BY num,
nth_value(num, 5) OVER ORDER BY num
FROM tDoes any other language implement this in a better way? While also still giving a O(n) time complexity and O(1) space? I may have to implement my own top-n heapsort then, or my own top-n insertion sort.
SELECT * FROM (
SELECT
row_number() AS n, num
FROM t
ORDER BY num DESC
LIMIT 5
) top5 WHERE n IN (1, 3, 5);
This is assuming we do not care about ties. If we care about ties it gets a bit messier but not that bad.Why not just use an Option/Maybe type?
> Why not just use an Option/Maybe type?
We are considering adding algebraic types and a syntax to match them, but it ultimately boils down to taste and use case:
SELECT value ?? "fallback in case of empty"
is not fundamentally different from (hypothetical): SELECT
MATCH value
CASE Some(non_empty_val) THEN non_empty_val
CASE Empty THEN "fallback in case of empty"
END;It still sounds like NULL -- I must be missing something.
SELECT 'one' IF value = 1 ELSE 'not one'
If value is an empty set, then the result is _always_ an empty set, unlike SQL that pretends NULL values are actually boolean for the purposes of the condition. EdgeQL expressions are, essentially, set comprehensions, the above is equivalent to this Python expression: {'one' if v = 1 else 'not one' for v in value}What would be other alternatives to a declarative language like SQL? Prolog?
Date&Darwen formally pinned down what such a language has to look like in their three subsequent editions of "the third manifesto" (first edition roundabouts 1995). There are at least two fully operational systems that comply.
It would seem to meet all your constraints, and is well-studied.
Datalog will ALWAYS be a niche language, because it is designed for a certain type of computational mind. The vast majority will want to learn SQL due to its ease despite any shortcomings it may have.
Datalog suffers from some of the same problems that SQL does (different dialects). It does seem to me that Datomic and Datascript have the most intuitive syntax.
However (1) once you've ingrained all the counter-proactive habits of thinking and worked past the stumbling blocks that imperative and object-oriented programming models present, the conceptual jump from that to SQL is smaller; and (2) good, in-depth introductory materials don't materialize out of nowhere without demand. Your instructor was probably trying to do something good, both by introducing you to data processing in a language with fewer syntactical hurdles and in year-by-year incrementally improving the quality of introductory material by using it in instruction.
Datalog allows you to express data relationships in a more straight forward, more compact, and easier to refactor way free of most boilerplate. It does, however, require you think about what you want to accomplish abstractly, rather than as an imperative process, which is difficult merely because of the years of experience the typical student already has in unergonomic languages like C++, Java, etc.
From a declarative sense datalog is much more concise than SQL. Depending on how you want to think about it, it also subsumes sparql.
The datalog compilers we're working on in our group create very efficient code and the evaluation strategy sometimes is far from what you would think of by looking at the query.
But since the result is defined as the minimal herbrandt model/fixpoint of the Tp operator you don't think about computation because you don't have to.
Could it be better? Sure, but author's proposal doesn't solve where I usually have problems. What are my pain points and what would I like to see instead?
1) One giant statement. Personally I really like Hadley Wickham's dplyr [1,2] (think "data pliers") which has a SQL like notion of joining different tables and selecting values but separates the filter, mutate and summarise verbs as separate steps in a pipeline rather than one huge statement. For transactions dplyr would have to add an update verb as well.
2) Hard to test, especially for more complex ETL. dplyr approach highlights that a lot of SQL these days is being used in ETL applications in addition to the usual retrieval, transactions and reporting. Being able to express as a pipeline of operations is easier for me to understand as execution is conceptually consecutive and I can unit test individual parts as part of a normal programming language environment.
3) My data isn't all tabular. Better support and semantics for non-scalar entries where value is a record itself like in json, BigQuery, Hive, Presto, etc.
4) Not that extendible. Better support for user defined operations (UDFs). More and more frequently I want to apply some non-trivial operation to data, e.g. run a machine learning model and it makes sense to do that as close as possible to the data usually. It is possible to do a fair bit in SQL itself with window functions but it is generally painful. You can point Hive at your jar and run a UDF but it is also painful to integrate and debug in my experience.
[1] https://cran.r-project.org/web/packages/dplyr/vignettes/dply... [2] https://datacarpentry.org/R-genomics/04-dplyr.html
Sure, SQL is not the most elegant language. But it works. It does what we need it to. Millions of developers knows it, countless tools speak it.
So I expect EdgeQL to go over like a lead balloon. Unless you can convince one of the big existing SQL servers to adopt it, almost no one will ever get the chance to use it, and it'll be a niche language for a niche database.
Something I wonder though; can materialized views be created with EdgeQL? And if so, does updating materialized views still require fully rebuilding them, as PostgreSQL does, or can they be updated incrementally?
Like mathematical syntax fits mathematical logic. So SQL matches data retrieval. Let's stop trying to replace it just because it's old. SQL is amazing.
His criticisms are nothing new. Relational "gurus" Date, Codd, Darwin, Fabian Pascal all made similar criticisms of SQL over the last 30 years.
I think the issue - for me - with articles like this is the tendency to take the stance of "${EXISTING_TECH} sucks, let's drop it for this new thing"
I would have found this way more compelling if this line was the very first in the article:
> The relational model is still the most generally applicable and effective method of representing data.
I think Datalog is a better alternative. However, for SQL or DBMS is a field with more powerful lock-in than other fields. Or Oracle wouldn't live so long so well without significant improvement over these years.
Your architecture shouldn’t start with an implementation choice. It should start with business modeling and drive down to tech choices, which may be one of many types of serialization/data storage technology.
Adopters of Domain-Driven Design have already moved past this argument.
> In EdgeQL, sets are flat, i.e. a set (including an empty one) cannot be an element of another set
It seems like in the last example, they're returning a set (of movies) that contains other sets (directors, cast, reviews). Am I misunderstanding? I guess it would be helpful to see what the output looks like for these examples.
The last query is still returning a flat set of Movie objects. The shape selector describes _related_ data that is also needed to be fetched by the query. So, the query actually returns multiple sets that can be reconstructed by the client into a graph of objects (or serialized into JSON).
Maybe. I would suggest tight budgets and lack of talented DBAs are the two primary reasons NoSQL became a thing. "We can make do without a SQL DBA."
No. You can't. IMNSHO
(edit: I'm specifically wondering about Rust, if it matters)
Any links to the HTTP-JSON API documentation? I've not found it thus far. (edit: I hope it's a fully featured API, and not the GraphAPI haha)
I absolutely hate working with graphQL, and document stores are a non-starter for projects with any decent amount of data.
Visit rosettacode.org and try looking up some solutions in SQL and then reference the APL variant. It's night and day.
Does this mean that "SELECT 1 + {}" gives "{}"?
The generalized conjuction (we have a function called "all" for that) of an empty set is True (the identity for conjunction).
The generalized disjuction (we have a function called "any" for that) of an empty set is False (the identity for disjunction).
All of the above "sum", "all", and "any" are basically aggregate functions that operate on sets as a whole.
There is no special logic that you wouldn't get from considering these operations generalized for a set.
"sum({1, 1, {}})" - the function sum takes only one argument and it's a set. Because we flatten all "nested" sets, the expression "{1, 1, {}}" is equivalent to "{1} UNION {1} UNION {}".
The expression "1 + 1 + {}" albeit valid grammatically, can be equivalently re-written as "{1} + {1} +{}". At this point it should be far more obvious why "sum({1} UNION {1} UNION {})" is not the same as "{1} + {1} + {}".
Literals may be a little confusing because they look like elements, but they are still sets, singleton sets, specifically. There's practical value in simply thinking about "a bunch of things: A, B, C", where each of the A, B and C can themselves be empty, a single thing, or a bunch of things while ignoring nesting. In our case we allow duplication in these bunches (which is not part of the bunch theory: http://www.cs.toronto.edu/~hehner/bunch.pdf). However, because most people are familiar with sets we find it easier to keep using the terms "set" and "multi-set" (and stipulate that they are flattened) in explanations.
In general, the way the operator "+" works is this: A + B = {a + b : for all a in A, for all b in B}. Whereas the expression "{A, B}" is defined to be equivalent to "A UNION B".
One more question: What was the motivation behind defining "sum({})" to be "0" rather then "{}" ?
sum(A UNION {}) = sum(A) + sum({})
sum(A) = sum(A) + sum({})
0 = sum({})
Typically for any operation generalized for a set the result of op({}) should be equal to the identity for that operation (0 for sum, 1 for product, True for AND, False for OR, etc.). It's always such a value I that for any other value A, A op I = A.
This would not happen if "sum({a, b})" was defined as "{a} + {b}" (which is what a user would intuitively assume). However, this definition is also not very practical as any one occurence of {} in the sum would render the whole thing to {} (which is not what a user would expect).
I guess the handling of "{}" will always stay a bit tricky.
Alternatively, if making the property required is not possible due to some workflow constraints, you could do "SELECT Payment{customer} FILTER NOT EXISTS .balance" to find all payments (and the associated customer), which don't have any balance set. Then once you know what they are you might use "UPDATE" to fix the problem.
Empty sets have fairly well-defined and consistent behavior w.r.t. functions (and operators). You learn it once and it applies in all contexts - specifically that empty sets are just sets like any other.
So, I still think that the definition "sum({}) = 0" has more potential to hide errors than the definition "sum({}) = {}" would have.
1) It's a little unlikely that at the same time you have data where an {} is an error, but you are not making the property required AND with knowledge of that you still don't bother with other validation approaches. The point is that if you're aware that this property is potentially incorrect, you would want to check or restrict it. But yes, if this situation is completely unexpected, then "sum" won't notice any issues.
2) You have to remember that {} can arise from perfectly normal operations, such as filtering. So if you filter by a certain date range and there's no Payments there, then "(SELECT Payment FILTER .timestamp > <datetime>$date).amount" expression becomes {} even if the "amount" property itself is required. So doing a sum over it is simply a question of "What's the total amount in payments since $date?" and if there aren't any payments, the answer is 0, not {}. Plus what you certainly don't want is to get an {} from the "sum" here and do "{} + 100" to add some other charge (perhaps a sum from a different account) and still end up with {}, which now creates an error in a situation where there's nothing wrong with the data.
3) Rather than imbuing {} with special meaning to signal errors, a separate property would be more appropriate. Such as a boolean "valid" flag that gets set after the record checks out or can even be a dynamically computable expression that looks at the record (say, Payments from our example) and does something like "valid := EXISTS .amount". Then you'd filter things by the valid property before feeding them to "sum" like so:
SELECT sum( (SELECT Payment FILTER .valid).amount );Over the past years I've seen many programmers struggle with the combination of "data aggregation" and NULL. In the beginning I thought that these programmers should just "RTFM", but as this problem occurs so often it might very well be that the practical implementation of aggregation and NULL is "a bit off".
I like your "set" approach a lot, however, we still have "sum({1, 1, {}})" unequal to "1+1+{}" and "sum({}) = 0" which, while consistent, I think are somewhat counterintuitive and I am pretty sure will lead to misunderstanding.
Having said that, I suspect that any decent and consistent approach to this problem is subject to a very reduced form of John Lydgate's famous quote, that is "You can only please some of the programmers some of the time".
Many thanks for your time and this interesting and insightful conversation.
I'm really interested in what other developers think about this.
A := select col_1, col_2, col_3 from table_1
B := select col_4, col_5, col_6 from table_2 where 2*col_5 > col_4 + col_6
$A left join $B on table_1.col_1 = table_2.col_5I heard this not too many years ago, and I am now very skeptical based upon those results.
There are many real life problems with SQL but this doesn't feel like it's resolving any of them.
Also I am not sure how it's better yet. SQL is typed and has a ton of historical overhead and used in many different database softwares.
This kind of just seems like a slightly different implementation of NoSQL syntax.
EdgeQL is strictly typed, here's more info: https://edgedb.com/docs/edgeql/overview/
> slightly different implementation of NoSQL syntax.
I'm genuinely curious what NoSQL syntaxes you are referring to.
Yes, I understand the theoretical rationale behind three-value-logic. Over here where I'm getting actual work done, it's nothing but an obstacle.
People of HN: if you really want to make money, make a open source (open core or whatever) horizontally scalable version of Versant OODBMS (Object-Oriented DBMS).
Hopefully a transpiler API is in the works for all of those wonderful standards deviant implementations?
In EdgeQL the keywords are recognized in any case. It is a matter of personal style.
- Lack of interoperability with other languages.
- General ugliness of server-side SQL (stored procedures and functions).
--------
The first one isn't really solved by ORM tools, AFAICT. You can't simply write the SQL query and transpile it into a nice, statically-typed method (with types derived from the actual database structure!) that you can call directly from your language.
For example, the database structure (I'm using T-SQL types here):
CREATE TABLE T (
A int PRIMARY KEY,
B bigint NOT NULL
);
And the query (T-SQL style parameter syntax): SELECT A, B FROM T WHERE A = @a;
Would produce the following method after transpilation (C#, hopefully self-explanatory): IEnumerable<(int A, long B)> Query(int a);
But when the database structure changes, that would automatically be reflected in the client language (after a build). For example, making B NULL-abe would produce: IEnumerable<(int A, long? B)> Query(int a);
--------The second gripe is not very important if you use SQL just as a client-side query language. But making the database "defend" its data (in presence of complex business logic, or security requirements, not fully expressible through declarative constraints) is still best achieved by "funnelling" all clients through an API of stored procedures/functions/views, IMHO. As a bonus, this approach also tends to lower database round-trips.
There seems to be a general lack of composability/reusability:
- E.g. one stored procedure returning a set of rows cannot just "pipe" them into another procedure or query - it must first copy the rows into a (temporary) table.
- If your dialect allows you to declare a table variable, you cannot just assign it to another, you have to INSERT.
- You can reuse the same SQL fragment multiple times in the same query (through WITH), but not in different queries without encapsulating it in a function (and good luck with performance if your dialect doesn't inline function query plans or doesn't support functions at all).
- You cannot parametrize ORDER BY, GROUP BY, IN...
And myriad of other problems:
- The syntax is stuck in the '80ties, not well suited for auto-completion, no type inference.
- Lack of simple struct/tuple types in some dialects (may lead to huge parameter lists).
- Inconsistent exception / error handling behavior (sometimes the transaction is aborted, sometimes it isn't).
- Silent data truncation in some cases.
- NULL sometimes meaning "unknown" and sometimes "empty".
- No boolean expressions (e.g. you can't write A IS NULL = B IS NULL).
- And probably many more that are currently not at the top of my head... <RANT CLOSED>
It strikes me that we can do better on all these fronts (and more), without abandoning the "good" parts of relational databases.
[ ] You cannot parametrize ORDER BY, GROUP BY, IN...
[v] type inference
[v] tuples, tuples of tuples, arrays of tuples, any combination, really
[v] Consistent exception / error handling behavior
[v] No silent data truncation in some case
[v] no NULLs -- empty sets are way more precisely defined in EdgeQL
[v] boolean expressions
Please give EdgeDB a try. Feedback from advanced SQL users is very important to us.
I mean, I don't necessarily claim that this is not a solution, it just isn't obvious to me at all. Maybe a more extensive explanation with better examples would make it all clear to me and I'd be super-hyped about it already, but right now I'm more like confused.
First off, it would be helpful show the table structure in the examples, and then compare EdgeQL query to the easiest solution in the SQL. After all, the readers supposedly use SQL almost daily for many years (I know I do), but don't know a thing about EdgeQL, so if it can do everything SQL can, but easier, such a comparison must make it pretty obvious.
TBH, my knowledge of the relational algebra is quite rusty by now, so maybe that's the problem, but as I remember, many queries we commonly use with the SQL are not really "relational" queries. Relational algebra deals with the sets of tuples, so things like count(*) or ORDER BY, or GROUP BY are not really a part of relational model, they just exist because they are super-helpful in what we usually are trying to achieve with SQL.
The problems with NULL are of a similar nature. I don't think we should pretend that NULL not being equal NULL is not useful (we don't expect "missing data" to be exactly the same value as another "missing data", do we?), and SELECT DISTINCT treating them as equals is not intuitive (for me it absolutely is: when I'm asking what values occur in a table, a missing entry is a missing entry to me, I don't want to see NULL 10000 times).
So, the introduction kind of made me to expect the solution to be more in compliance with relational concepts, but it doesn't seem to be, since all of the above are present in the EdgeQL in one form or another.
I'm not sure how {} is different from NULL in the EdgeQL, since {} seems to be kind of special thing here, the same as NULL is in the SQL. I mean, it doesn't behave like a true empty set at all! Non-empty set {value} OR {} = {value}, not {} (OR ≡ ∪). <bool>{} being {} instead of a true boolean value looks even more confusing to me than NULL OR (NOT NULL) = NULL. Same ternary algebra here.
Then, I don't really understand a concept of a flat set here. I do kind of understand what we are trying to achieve here: we want to solve the problem of SELECT x, (SELECT y) FROM z throwing an error in a runtime, if count(SELECT y) != 1. And it kind of would make sense in SQL, but it's explicitly advertised as a feature of EdgeQL that it can return trees (json-like structures), and here it doesn't seem to make sense that an output of a query (which is a "flat set", I guess?) cannot have another set as an element. Moreover, it obviusly can be ordered, which also isn't a property of how "set" is commonly defined in the set theory.
As a first impression, syntax and overall structure of the queries doesn't strike me as obvious as well. In fact, since
> SQL does not integrate well enough with application languages and protocols
I would ultimately hope for something that can be expressed as a number of function calls and commonly used data structures (a list, a dictionary/record, etc.) in most/any mainstream PLs, not a one more DSL as in "free form text". (Maybe with a more succinct DSL for the use in a console. Maybe.)
And my ultimate source of confusion. SQL is more or less the same thing even in these DBMS where it isn't exactly The SQL (like ClickHouse). And given I know the overall structure of the DBMS (like, is it, for instance, row-based or column-based?) I can make pretty good assumptions of performance of a given query, even though SQL is still declarative and I do not know what exactly the query-optimizer will do. Maybe it's just that I'm not used to it, but I don't have a feel about how performant would be the last EdgeQL example of the article, and if it would be better to separate it into several queries at some scale. In fact, I don't even understand if it's something that would be reasonable easy to implement in other major RDBMS', or is it ultimately EdgeDB-only feature? If so, it can be only as good as EdgeDB — and is it as good as PosgreSQL, or MariaDB, or sqlite? Unfortunately, in the real world I have to worry more about how performant and robust a thing is under load, than I can worry about programming convenience.
This is because we define infix OR as
{a OR b | ∀ (a, b) ∈ (A x B)}
Same goes for the cast function.
You may argue that this is confusing, but if you think about everything as a set comprehension, it is way more consistent. For example the `CASE WHEN` example from the post would always return `{}` for empty input, making it obvious.
> but it's explicitly advertised as a feature of EdgeQL that it can return trees (json-like structures)
The tree-like return is not an aspect of a language system, it's a matter of output representation. For example:
SELECT User { favorites: {name} }
still returns a flat set of User objects. The shape selector `{ ... }` is an annotation that defines how an object is serialized in the output.> I would ultimately hope for something that can be expressed as a number of function calls and commonly used data structures
This is exactly where we are going. Orthogonality in the underlying language makes it much easier to achieve this.
> and is it as good as PosgreSQL, or MariaDB, or sqlite?
EdgeDB is based on Postgres, we actually transpile EdgeQL to SQL. EXPLAIN and query performance analysis are being worked on.
> in the real world I have to worry more about how performant and robust a thing is under load, than I can worry about programming convenience.
We have posted some benchmarks [1], and more are coming.
Let me guess: ya can't.
I'm not sure this part is realistic to do in a non-trivial setup. At the very least it's not a common thing to do.
I don't think NULLs are actually a problem in SQL. It's not like we're talking about pointers, it won't cause your server to crash if you use them wrong. NULLs in SQL are fine.
The MongoDB example is extremely contrived. If you wanted to do that with MongoDB you would add a new field or a new collection with full_name rather than doing a $map.
MongoDB has a way to fetch data the way we needed and the way other databases fetch it in our benchmarks. We tried just that: the performance is roughly the same anyways. It's up to MongoDB users how exactly they store the data and how exactly they query it, but it's nice to know that their query language is capable enough.
I think that it's pretty obvious that not a lot of users query data like that in MongoDB and instead just store denormalized data. That's not the point of that blog post though.