Category : Paradox DBMS
Archive   : TECH91.ZIP
Filename : TI616.ASC

 
Output of file : TI616.ASC contained in archive : TECH91.ZIP








PRODUCT : Paradox NUMBER : 616
VERSION : 3.0 & up
OS : PC DOS
DATE : September 11, 1991 PAGE : 1/1

TITLE : Use of the Paradox Resynckey with linked tables




Use of the Paradox Resynckey with linked tables relies on the
relationship for key field updating.

When changing the value of the master table field which is being
used as a link to a detail table, that linking field in the
detail table will be changed if the relationship between tables
is One-to-One or One-to-Many.

In a Many-to-One or Many-to-Many relationship, the key field of
the detail table would not be changed, and the new matching
detail records would appear as you would expect to happen.

The following chart shows the relationships ...

ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÑÍÍÍÍÍÍÍÍÍÍÍÍÍÍÑÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
º Relationship ³ Owns Details ³ Changes Detail Keys º
ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ
º One-to-One ³ YES ³ YES º
º One-to-Many ³ YES ³ YES º
º Many-to-One ³ NO ³ NO º
º Many-to-Many ³ NO ³ NO º
ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÏÍÍÍÍÍÍÍÍÍÍÍÍÍÍÏÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ


Many users will often make the mistake of thinking RESYNCKEY will
resynchronize the detail with the new master values all the time,
or report that on one table it works, but on another it doesn't.

The proper relationship for using RESYNCKEY should be a Many-to-
One or Many-to-Many. In addition, in a One-to-One and One-to-
Many relationship, Paradox always automatically changes the
detail key fields when you change the linking master table
fields.