Question Backlog for Valentina mailing list.

[Ed Kleban]

On 11/15/05 11:55 AM, "Ed Kleban" <Ed at kleban.com> wrote:

> 
>> Ok, great. Now I understand. :)
>> 
>>> Only not complete yet:
>>> 
>>> * you talk only about ObjectPtr always.
>>> 
>>> * Valentina 2 have also link - FOREIGN KEY.
>>>     it is similar to ObjectPtr by nature. It is a field.
>> 
>> Yes, certainly.  And in a full discussion it should be mentioned as well.
>> But of course it's the ObjectPtr aspect that offers the great performance
>> and appeal to me and which I intend to use, so it was on the top of my mind
>> in trying to understand this.
>> 
>>> * Valentina 2 also have new link -- BbinaryLink. This is not a field at all.
>>> 
>>> Methods of Vlink class work for ALL link kinds. So it needs write text in
>>> general form.
>>> 
>> 
>> Yes. I understand and agree.  First I had to understand what it did.  I could
>> write something that would serve all cases now.   I very much like
>> the concept of the Vlink; making the links be an instantiated abstraction
>> is very cool.   
>> --Ed

Well, I take that back.  I clearly don't understand.  Last night in bed I
started wondering:

"I wonder if there's a way to simply use a byte-wide field as you would use
an ObjectPtr field if it is known in advance that the linked-to table will
never have more that 255 records? "

Then I thought, "Hmm. maybe that's what Binary Links can do if you create a
link between a byte-size field in one table with the virtual RecID field in
another table."

But I just now read all the doc in both the Kernel and RB Reference about
Binary Links and decided I don't have a clue about what they do or how to
use 'em.

Specifically:  The constructor VBinaryLink takes as arguments a pair of
tables, and some referece ("power") , deletion, and storage arguments -- but
has no field arguments.  So my conjecture that it could relate specific
fields was clearly wrong, that's not what it does, nor is that what the
documentation says it does.  In fact as the doc clearly states it doesn't
require field allocations.

So I guess I'm stuck.  I don't understand these critters.  I understand how
to create a binary link with VBinaryLink(...), but I don't know how to use
the link once I have it.  How do I tell the link, or how does the link know,
which records in Table A correspond to which records in Table B, or vice
versa?

--Ed