将过程代码展开为 SQL
最近我对将过程代码转换为 SQL 的行为很感兴趣。我知道并不是所有的事情都可以用图灵完备的过程语言来表达。
如果您有特殊用途的过程语言怎么办？例如将这样的东西转换
foreach(var row in Table){
if(row.FirstName=="Foo"){
yield new {row.TableRID};
}
}
成这样：
select TableRID from Table where FirstName='Foo'
这样的东西有名字吗？
另外，在我的伪代码中假设 row 是不可变的，并且不可能执行诸如 Table[0].FirstName... 之类的操作以及其他显然没有 (简单）翻译成 ANSI SQL。
谁能给我这个的名字吗？
The act of transforming procedural code into SQL has been of interest to me lately. I know that not absolutely everything is expressable in a turing complete procedural language.
What if you have a special purpose procedural language though? For instance converting something like this:
foreach(var row in Table){
if(row.FirstName=="Foo"){
yield new {row.TableRID};
}
}
into this:
select TableRID from Table where FirstName='Foo'
Is there a name for something like this?
Also, in my psuedo code assume that row is immutable and it is impossible to do something like Table[0].FirstName... and other things which obviously have no (easy) translation into ANSI SQL.
Can anyone give me a name for this?
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一切都可以用图灵完备的过程语言来表达。但它并不总是富有表现力。有时，您可以通过消除权力、为您想要解决的问题创建一种特定于领域的语言或DSL来获得表现力。也许这就是您正在寻找的术语？
没有扩展的 SQL 不是图灵完备的，因此正如您所注意到的，只能转换图灵完备语言的可能程序的子集。
Everything is expressible in a Turing-complete procedural language. It's not always expressive, though. Sometimes you can gain expressiveness by removing power, creating a domain-specific language, or DSL, for the kind of problem you want to solve. Maybe this is the term you are looking for?
SQL without extensions is not Turing-complete, so as you note, only a subset of the possible programs of a Turing-complete language can be transformed.