Link/Unlink Records M:1 ?

[Ruslan Zasukhin]

On 15/7/07 11:21 PM, "Barry G. Sumpter" <BarrySum at BigPond.Net.AU> wrote:

Hi Barry,

> http://www.valentina-db.com/dokuwiki/doku.php?id=paradigma:public:en:documen
> tation:vsql:reference:insert_link&s=unlink
> 
> 
> Is it OK to use a M:1 Binary Link?
> This scenario is missing from the above link entitled:
>  Valentina SQL: LINK/UNLINK Records

Actually M:1 link is 100% symmetry of 1:M link.

It is only issue of order of tables when you create a link.
For example:

1) tables Person and Phone linked as 1:M

    CREATE BINARY LINK linkname(Person, Phone) AS ONE TO MANY


2) tables Phone and Person linked as M:1

    CREATE BINARY LINK linkname(Phone, Person) AS MANY TO ONE

I.e. You always can design your db to have all Binary Links as 1:M.

 
> I'm hoping I can use:
> UnLINK RECORD(1) OF Person USING PersonHasPone

Yes should work.


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

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