Re: Object-relational impedence

From: Marshall <>
Date: Wed, 5 Mar 2008 07:58:43 -0800 (PST)
Message-ID: <>

On Mar 4, 11:10 pm, Robert Martin <> wrote:
> On 2008-03-03 18:34:39 -0600, Marshall <> said:
> > In SQL, if I have two relations with x and y int columns, I can
> > union them, or join on them, or whatever. There is no way,
> > in fact, to forbid such a thing, just like in Java there is no way
> > to allow such a thing.
> You are confusing OO with static typing.

How supremely annoying to have gone to some lengths to carefully use the most strictly defined, modern type system terminology, only to have it labeled as a novice error by someone who missed my point entirely.

At least you didn't say "duck typing."

> In OO languages like Ruby,
> Python, or Smalltalk you can pass any object to any function
> irrespective of type.

Actually, the dimension I was referring to is "nominal" vs. "structural" typing. This axis is independent of static vs. "dynamic" typing. Ruby, Python and Smalltalk all use structural, dynamic (aka runtime) typing. C++ uses static, nominal typing. Java uses a static, nominal type system with the addition of runtime types; SQL uses static, structural typing.

I was speaking of nominal vs. structural.

Marshall Received on Wed Mar 05 2008 - 16:58:43 CET

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