6 ms·

SQL is not a declarative language. It is a functional language, and structured language on the top as extensions. HTML is a declarative language.

luhn 4y ago
> Although SQL is essentially a declarative language (4GL), it also includes procedural elements. https://en.wikipedia.org/wiki/SQL https://en.wikipedia.org/wiki/SQL
- spamtarget 4y ago
  -3 votes shows how this is a common misunderstanding. If SQL was a declarative language, there would not be expression in it, for example SELECT (1+2) , only SELECT 3 These categories based on the approach of the programming, not the underlying technology. Imperative languages (high level): a step-by-step description of a process, like giving orders to someone/something in a sequence, organized further with loops and conditions. Analogue: cooking recipe. Languages: C, Pascal, Basic, etc (they can be structured or object oriented, still imperative) Functional language (not mathematical definition, forget stateless, non-mutable etc for a moment): It is an approach that solves the problem of cardinality of the imperative approach. There is nothing which is "one", only "one of them". It's a little bit confusing how i try to define this, but this is the most important aspect of this. We only filter and transform elements of a set, and even if this is nothing (for not mathematical aspect), but syntax sugar, it gives a programmer a safe way to do things, without caring about the details of enumerating things or null checks, etc. Or another angle: functional programming eliminates loops, and put the sequence in the data, and keep conditions. It is really handy to be honest. Purely functional languages are mostly experiments, because making something functional is kinda self-motivated, but other languages will pick up more functional elements in time, which is great. Analogue: assembly line in a factory. Thing are coming, they are changed (like car body painted) or removed (like quality control). Languages: LINQ, SQL, F# Declarative language: your approach here is instead of describing how to do something, you only describe what you want as a result. CSS is a perfect example, however it is picking up non-declarative elements nowadays, original it was only capable to describe how a font a paragraph look like. HTML is also declarative. Instead of actually drawing a rectangle, you just say, this width, height on this position, etc. Analogue: you order a coffee in coffee shop. You don't care any of the details, just the parameters of the coffee you want to drink. Languages: HTML, CSS Of course there are blurred lines like you can say all high level language are declarative, because you never go down to the hardware level to manually do everything, but I think what is important the approach, how you start to solve the problem, and if we see this from this point, SQL cannot be a declarative language. It was designed to be as close to English as possible to make non-IT people do programming, but it successfully failed it's purpose, because it is a pretty good language for programmers, but it was never designed to be declarative.
  - OJFord 4y ago
    > If SQL was a declarative language, there would not be expression in it, for example SELECT (1+2) , only SELECT 3 SQL is I think generally considered not entirely declarative, but that is not an example that shows that. Is there any declarative language that satisfies that, that has no addition (or operator? Or addition of constants? I'm not really clear what about it you think makes it not declarative?). By this rule, Prolog and HCL/Terraform are not declarative either.
    - spamtarget 4y ago
      one way of seeing this, everything, which is high level language is declarative, but if we do this, we make this classification meaningless. it was just an example, for an operator, which is an "activity" is not part of a declarative mindset (usually). you can twist the idea of SQL to be declarative, but in this case we go back to my first sentence, and distinction will have no purpose. i give you other angles. imperative has structures like: sequence (by code), loops and conditions functional ** has no loop, the loop itself the cardinality, which is always multiple ** has no sequence, it's encoded by data (edit here, actually it has) ** has (of course) condition So, by basically we redefine the fundamental elements of the imperative model Purely declarative languages has no sequence/loop or conditions (in programming understanding) Answering to you, HTML (especially earlier) is pretty close to purely declarative, i does not have loops or conditions, however, this is not 100% true, but close. I don't know those languages you mentioned, so i can not have an opinion about them
  - Izkata 4y ago
    > Declarative language: your approach here is instead of describing how to do something, you only describe what you want as a result. CSS is a perfect example, however it is picking up non-declarative elements nowadays, original it was only capable to describe how a font a paragraph look like. HTML is also declarative. Instead of actually drawing a rectangle, you just say, this width, height on this position, etc. SQL fits this perfectly. For example JOINs don't describe actions, they describe relationships. Have you ever looked at what the query planners come up with to satisfy those relationships?
recursive 4y ago
The most important requirement for a functional language is that functions are first-class values. i.e. Not SQL. On the other hand, the details of query execution are left to the planner and optimizer. What's the case that it's functional, but not declarative?
- spamtarget 4y ago
  You are speak about things which called delegates, typed functions, defined by the parameters it gets, and the data it returns. Using delegates does not make a language functional. If you really want to speak about the underlying technology, than every high level language is declarative. You can draw a triangle by drawing three sides, or you can just put this in a function like drawtriangle(v1,v2,v3), and tadam, your language is declarative. The underlying tech is not important, the approach of the developer is important. See my longer answer above
  - yakshaving_jgt 4y ago
    Your comments in this thread have made for a pretty tough read, but I think your angle is finally made clear here. Supposedly, “every high level language is declarative”. It’s an opinion I suppose, but I doubt it’s one you’re going to find much support for. What I think this feels like to most people is that things aren’t what people think they are because you’ve decided to reimagine the commonly used definitions of the words used to describe those things. Not sure if it’s a straw man exactly, but I feel like I’m in a straw man’s garden.
    - spamtarget 4y ago
      I'm sorry, i'm speaking with multiple people on multiple threads here, and don't have too much time to express myself perfectly. Every language is declarative is an interpretation that can make sense in certain angle, like when you use some imperative language, you create mini libraries for yourself, and that's already steps to a declarative variation, but this does not changes the fundamental design of the language. But this is not my angle, i say the borders drawn up by the way how you, as a programmer, approach solving a problem. My take is declarative when you define the *end result* you want to get. You certainly don't do this with SQL, because that case the your product (what you write in the query) would be the end result set, the data itself. Of course in case of HTML you don't literally draw in the rectangle in the code, but you describe the end result. This is the difference. Other arguments you wrote is out of scope for me regarding this conversation.
mLuby 4y ago
You tell SQL what you want, not how to get it. That's declarative. SQL : CSV :: GraphQL : JSON :: React : HTML
- spamtarget 4y ago
  Really? SELECT CASE WHEN employee.type = 'contract' THEN salary CASE WHEN employee.type = 'full-time' THEN salary + benefit_costs END CASE FROM employee Tell me how is this declarative? -SQL is functional -CSV is not a language, it's a data format -GraphQL, im not familiar -JSON is literally executable javascript code, arguable -React is a javascript framework, binding is a declarative nature (if it has it, i dont know it too well), but it is not a language, it's a framework -HTML is absolutely, 100% declarative, yes
  - preseinger 4y ago
    Does the presence of conditional expressions mean that the language which permits them is necessarily not declarative?
    - spamtarget 4y ago
      no, the approach makes the difference. when you create html, you dont care how the rectangle is drawn, you focus on defining the result itself. if sql was declarative, than the code of the SQL above would be: GIVE ME ALL THE COST OF THE EMPLOYEES --, I DONT CARE ABOUT THE DETAILS the details, which in this example the difference between fulltime/contract employees would be handled by the framework (SQL server) which would already has a concept of two kind of employee like in HTML can have rounded tips of rectangle or angular tips, because the framework already understand these ideas an SQL query itself (if no structured language used) is just a big function applied on a set. It has never have a concept of the things you do, like building an accounting solution to a company. HTML has the concept of paragraphs, button, etc etc, all the things you wanna do. but with SQL you step by step define what you want by conditions and transformations. or another way to separate them -imperative is a combination of -sequence/condition/loop -function -no loop (cardinality is always multiple) -sequences is encoded as data -conditions <- yes it has conditions
uticus 4y ago
Okay, I'll grant it's not pure declarative. But the part that is declarative is sure difficult to test.
- spamtarget 4y ago
  everything is partly declarative. you can draw a rectangle line by line, or you can put this code into a function or a procedure, and call it declarative, because it is something like that. i did not speak about testing, however what a declarative language can do is defined by the framework under it. so you test that I guess?
  - ttfkam 4y ago
    SVG: Draw rectangles and triangles. If you don't have a script tag in it, totally declarative. You don't draw line by line. You describe what you want and have the engine work it out. Just because that description can be complex such as a <path> definition doesn't detract from this point. Kinda like SQL. Describe the set of data you want from other sets of data and have the engine work it out. It's set theory. In math, sets can have conditions, can be combined, can be filtered, and all without a single function or loop in sight. Ergo declarative, not functional or imperative. SQL is a DSL for set theory with some extensions tacked on. You can use functions with SQL, but its core is perfectly adequate without them.
    - spamtarget 4y ago
      >SVG: Draw rectangles and triangles. If you don't have a script tag in it, totally declarative I totally agree. It is declarative the same way how HTML is. I don't see how SQL and SVG is similar from the viewpoint of approaching the problem. In SVG you concretely define what you want, and that is happening. In SQL you don't define the data you get, like ok, this cell will be 5, another will 8. I understand what you want to say, I just see those completely different ways. >can be combined, can be filtered, and all without a single function or loop in sight This is the key here, because this is exactly true to functional programming. Compare SQL->LINQ->lambda expression If they work the how you say, then SQL - declarative LINQ - declarative and functional the same time Lambda exp - functional This idea is completely nonsensical for me
taeric 4y ago
I mean, I get what you are aiming for. HTML, though, is a markup language. You can call it declarative, but you don't get anything other than the HTML that you create. That is, it is not generating anything. You type what you get. Put differently, it is not a program. SQL is far and away understood as a declarative language for what data you want out of a relational database. I challenge you to find any literature that does not describe it as a declarative language. Now, can we munge definitions and pull in an odd true scotsman argument about it not being a "true declarative" language? I mean, yeah. But, this is like arguing that LISP is not a functional language by some specific modern view of that term. Certainly true, but far from useful. And almost certainly not what anyone you would talk to expects from those terms.
- spamtarget 4y ago
  "don't get anything other than the HTML that you create" that's the point of declarative languages "That is, it is not generating anything." if you speak about code generation like code behind in VS, it has nothing do with the paradigm. If you speak about underlying technology, it does not matter. In case of declarative languages, the framework determines what the language is capable of. And that's the point of them, they are generalizing the solution for common problems. The browser do a lot of things in the background when it draws a rectangle the same way how SQL server is doing a lot things when you execute a query, but these things have nothing to do with programming paradigm, which can be understood without computers. Imperative: cooking recipe Functional: assembly line in a factory Declarative: your assistant (compare the real world examples to the things i mentioned) > SQL is far and away understood as a declarative language for what data you want out of a relational database. I challenge you to find any literature that does not describe it as a declarative language. Ok, and I challenge you to compare HTML and SQL. Are they the same by nature. Are the steps, the approach of problem solving is the same? Because if SQL is declarative, than it is really similar to HTML > Now, can we munge definitions and pull in an odd true scotsman argument about it not being a "true declarative" language? I mean, yeah. But, this is like arguing that LISP is not a functional language by some specific modern view of that term. Certainly true, but far from useful. And almost certainly not what anyone you would talk to expects from those terms. We are speaking about semantics and taxonomy here. These kind of a questions are always debatable, so i can't really say anything about this, because you are speaking of ways of discussion. What i'm saying that my taxonomy makes the most sense to me, and if someone truly can challenge it, it's gonna make my mind change, but "literature mentions it somehow else" is not an argument makes me change my mind.
preseinger 4y ago
SQL is absolutely a declarative language. It is practically the textbook definition of a declarative language.
- ttfkam 4y ago
  Very often literally as well.

luhn 4y ago

> Although SQL is essentially a declarative language (4GL), it also includes procedural elements. https://en.wikipedia.org/wiki/SQL https://en.wikipedia.org/wiki/SQL

spamtarget 4y ago
-3 votes shows how this is a common misunderstanding. If SQL was a declarative language, there would not be expression in it, for example SELECT (1+2) , only SELECT 3 These categories based on the approach of the programming, not the underlying technology. Imperative languages (high level): a step-by-step description of a process, like giving orders to someone/something in a sequence, organized further with loops and conditions. Analogue: cooking recipe. Languages: C, Pascal, Basic, etc (they can be structured or object oriented, still imperative) Functional language (not mathematical definition, forget stateless, non-mutable etc for a moment): It is an approach that solves the problem of cardinality of the imperative approach. There is nothing which is "one", only "one of them". It's a little bit confusing how i try to define this, but this is the most important aspect of this. We only filter and transform elements of a set, and even if this is nothing (for not mathematical aspect), but syntax sugar, it gives a programmer a safe way to do things, without caring about the details of enumerating things or null checks, etc. Or another angle: functional programming eliminates loops, and put the sequence in the data, and keep conditions. It is really handy to be honest. Purely functional languages are mostly experiments, because making something functional is kinda self-motivated, but other languages will pick up more functional elements in time, which is great. Analogue: assembly line in a factory. Thing are coming, they are changed (like car body painted) or removed (like quality control). Languages: LINQ, SQL, F# Declarative language: your approach here is instead of describing how to do something, you only describe what you want as a result. CSS is a perfect example, however it is picking up non-declarative elements nowadays, original it was only capable to describe how a font a paragraph look like. HTML is also declarative. Instead of actually drawing a rectangle, you just say, this width, height on this position, etc. Analogue: you order a coffee in coffee shop. You don't care any of the details, just the parameters of the coffee you want to drink. Languages: HTML, CSS Of course there are blurred lines like you can say all high level language are declarative, because you never go down to the hardware level to manually do everything, but I think what is important the approach, how you start to solve the problem, and if we see this from this point, SQL cannot be a declarative language. It was designed to be as close to English as possible to make non-IT people do programming, but it successfully failed it's purpose, because it is a pretty good language for programmers, but it was never designed to be declarative.
- OJFord 4y ago
  > If SQL was a declarative language, there would not be expression in it, for example SELECT (1+2) , only SELECT 3 SQL is I think generally considered not entirely declarative, but that is not an example that shows that. Is there any declarative language that satisfies that, that has no addition (or operator? Or addition of constants? I'm not really clear what about it you think makes it not declarative?). By this rule, Prolog and HCL/Terraform are not declarative either.
  - spamtarget 4y ago
    one way of seeing this, everything, which is high level language is declarative, but if we do this, we make this classification meaningless. it was just an example, for an operator, which is an "activity" is not part of a declarative mindset (usually). you can twist the idea of SQL to be declarative, but in this case we go back to my first sentence, and distinction will have no purpose. i give you other angles. imperative has structures like: sequence (by code), loops and conditions functional ** has no loop, the loop itself the cardinality, which is always multiple ** has no sequence, it's encoded by data (edit here, actually it has) ** has (of course) condition So, by basically we redefine the fundamental elements of the imperative model Purely declarative languages has no sequence/loop or conditions (in programming understanding) Answering to you, HTML (especially earlier) is pretty close to purely declarative, i does not have loops or conditions, however, this is not 100% true, but close. I don't know those languages you mentioned, so i can not have an opinion about them
- Izkata 4y ago
  > Declarative language: your approach here is instead of describing how to do something, you only describe what you want as a result. CSS is a perfect example, however it is picking up non-declarative elements nowadays, original it was only capable to describe how a font a paragraph look like. HTML is also declarative. Instead of actually drawing a rectangle, you just say, this width, height on this position, etc. SQL fits this perfectly. For example JOINs don't describe actions, they describe relationships. Have you ever looked at what the query planners come up with to satisfy those relationships?

recursive 4y ago

The most important requirement for a functional language is that functions are first-class values. i.e. Not SQL. On the other hand, the details of query execution are left to the planner and optimizer. What's the case that it's functional, but not declarative?

spamtarget 4y ago
You are speak about things which called delegates, typed functions, defined by the parameters it gets, and the data it returns. Using delegates does not make a language functional. If you really want to speak about the underlying technology, than every high level language is declarative. You can draw a triangle by drawing three sides, or you can just put this in a function like drawtriangle(v1,v2,v3), and tadam, your language is declarative. The underlying tech is not important, the approach of the developer is important. See my longer answer above
- yakshaving_jgt 4y ago
  Your comments in this thread have made for a pretty tough read, but I think your angle is finally made clear here. Supposedly, “every high level language is declarative”. It’s an opinion I suppose, but I doubt it’s one you’re going to find much support for. What I think this feels like to most people is that things aren’t what people think they are because you’ve decided to reimagine the commonly used definitions of the words used to describe those things. Not sure if it’s a straw man exactly, but I feel like I’m in a straw man’s garden.
  - spamtarget 4y ago
    I'm sorry, i'm speaking with multiple people on multiple threads here, and don't have too much time to express myself perfectly. Every language is declarative is an interpretation that can make sense in certain angle, like when you use some imperative language, you create mini libraries for yourself, and that's already steps to a declarative variation, but this does not changes the fundamental design of the language. But this is not my angle, i say the borders drawn up by the way how you, as a programmer, approach solving a problem. My take is declarative when you define the *end result* you want to get. You certainly don't do this with SQL, because that case the your product (what you write in the query) would be the end result set, the data itself. Of course in case of HTML you don't literally draw in the rectangle in the code, but you describe the end result. This is the difference. Other arguments you wrote is out of scope for me regarding this conversation.

mLuby 4y ago

You tell SQL what you want, not how to get it. That's declarative. SQL : CSV :: GraphQL : JSON :: React : HTML

spamtarget 4y ago
Really? SELECT CASE WHEN employee.type = 'contract' THEN salary CASE WHEN employee.type = 'full-time' THEN salary + benefit_costs END CASE FROM employee Tell me how is this declarative? -SQL is functional -CSV is not a language, it's a data format -GraphQL, im not familiar -JSON is literally executable javascript code, arguable -React is a javascript framework, binding is a declarative nature (if it has it, i dont know it too well), but it is not a language, it's a framework -HTML is absolutely, 100% declarative, yes
- preseinger 4y ago
  Does the presence of conditional expressions mean that the language which permits them is necessarily not declarative?
  - spamtarget 4y ago
    no, the approach makes the difference. when you create html, you dont care how the rectangle is drawn, you focus on defining the result itself. if sql was declarative, than the code of the SQL above would be: GIVE ME ALL THE COST OF THE EMPLOYEES --, I DONT CARE ABOUT THE DETAILS the details, which in this example the difference between fulltime/contract employees would be handled by the framework (SQL server) which would already has a concept of two kind of employee like in HTML can have rounded tips of rectangle or angular tips, because the framework already understand these ideas an SQL query itself (if no structured language used) is just a big function applied on a set. It has never have a concept of the things you do, like building an accounting solution to a company. HTML has the concept of paragraphs, button, etc etc, all the things you wanna do. but with SQL you step by step define what you want by conditions and transformations. or another way to separate them -imperative is a combination of -sequence/condition/loop -function -no loop (cardinality is always multiple) -sequences is encoded as data -conditions <- yes it has conditions

uticus 4y ago

Okay, I'll grant it's not pure declarative. But the part that is declarative is sure difficult to test.

spamtarget 4y ago
everything is partly declarative. you can draw a rectangle line by line, or you can put this code into a function or a procedure, and call it declarative, because it is something like that. i did not speak about testing, however what a declarative language can do is defined by the framework under it. so you test that I guess?
- ttfkam 4y ago
  SVG: Draw rectangles and triangles. If you don't have a script tag in it, totally declarative. You don't draw line by line. You describe what you want and have the engine work it out. Just because that description can be complex such as a <path> definition doesn't detract from this point. Kinda like SQL. Describe the set of data you want from other sets of data and have the engine work it out. It's set theory. In math, sets can have conditions, can be combined, can be filtered, and all without a single function or loop in sight. Ergo declarative, not functional or imperative. SQL is a DSL for set theory with some extensions tacked on. You can use functions with SQL, but its core is perfectly adequate without them.
  - spamtarget 4y ago
    >SVG: Draw rectangles and triangles. If you don't have a script tag in it, totally declarative I totally agree. It is declarative the same way how HTML is. I don't see how SQL and SVG is similar from the viewpoint of approaching the problem. In SVG you concretely define what you want, and that is happening. In SQL you don't define the data you get, like ok, this cell will be 5, another will 8. I understand what you want to say, I just see those completely different ways. >can be combined, can be filtered, and all without a single function or loop in sight This is the key here, because this is exactly true to functional programming. Compare SQL->LINQ->lambda expression If they work the how you say, then SQL - declarative LINQ - declarative and functional the same time Lambda exp - functional This idea is completely nonsensical for me

taeric 4y ago

I mean, I get what you are aiming for. HTML, though, is a markup language. You can call it declarative, but you don't get anything other than the HTML that you create. That is, it is not generating anything. You type what you get. Put differently, it is not a program. SQL is far and away understood as a declarative language for what data you want out of a relational database. I challenge you to find any literature that does not describe it as a declarative language. Now, can we munge definitions and pull in an odd true scotsman argument about it not being a "true declarative" language? I mean, yeah. But, this is like arguing that LISP is not a functional language by some specific modern view of that term. Certainly true, but far from useful. And almost certainly not what anyone you would talk to expects from those terms.

spamtarget 4y ago
"don't get anything other than the HTML that you create" that's the point of declarative languages "That is, it is not generating anything." if you speak about code generation like code behind in VS, it has nothing do with the paradigm. If you speak about underlying technology, it does not matter. In case of declarative languages, the framework determines what the language is capable of. And that's the point of them, they are generalizing the solution for common problems. The browser do a lot of things in the background when it draws a rectangle the same way how SQL server is doing a lot things when you execute a query, but these things have nothing to do with programming paradigm, which can be understood without computers. Imperative: cooking recipe Functional: assembly line in a factory Declarative: your assistant (compare the real world examples to the things i mentioned) > SQL is far and away understood as a declarative language for what data you want out of a relational database. I challenge you to find any literature that does not describe it as a declarative language. Ok, and I challenge you to compare HTML and SQL. Are they the same by nature. Are the steps, the approach of problem solving is the same? Because if SQL is declarative, than it is really similar to HTML > Now, can we munge definitions and pull in an odd true scotsman argument about it not being a "true declarative" language? I mean, yeah. But, this is like arguing that LISP is not a functional language by some specific modern view of that term. Certainly true, but far from useful. And almost certainly not what anyone you would talk to expects from those terms. We are speaking about semantics and taxonomy here. These kind of a questions are always debatable, so i can't really say anything about this, because you are speaking of ways of discussion. What i'm saying that my taxonomy makes the most sense to me, and if someone truly can challenge it, it's gonna make my mind change, but "literature mentions it somehow else" is not an argument makes me change my mind.

preseinger 4y ago

SQL is absolutely a declarative language. It is practically the textbook definition of a declarative language.

ttfkam 4y ago
Very often literally as well.