Re: WHAT vs HOW vs WHERE

> "Laconic2" <laconic2_at_comcast.net> wrote in message
> news:4ZydnbnwtcNGGSXdRVn_iw_at_comcast.com...
> [...]
>
> 1) Is a "pointer" a value, variable, other?
> 2) Is a Java reference a type of pointer?
> 3) Is the name of a relation plue the name of an attribute a pointer to the
> values of such? That has two parts -- Can a pointer be a literal string?
> and Can a pointer point to a set?
>

A pointer is a special kind of type. One can declare variables of a pointer type, and these variables can have pointer values.

A pointer type is a type for which two operations are supported: referencing and dereferencing.

The dereferencing operation takes a pointer *value* and returns a *variable* of the type the pointer refers to.

The referencing operation is the inverse operation. It takes a *variable* and returns a pointer *value*.

Java references are pointers in the above sense. The term pointer was avoided in Java because the term pointer is often used in a more restricted sense, meaning physical memory addresses.

Relational keys are definitely not pointers.

--
Rene´ Hartmann