Cascade Update Related Fields Bug?

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Mike_iDbM - 27 Dec 2004 18:57 GMT

I have set up one to many relationship between an order table (master/one)
and a order details table (slave/many) using the related field orderID .
This field is the primary key in the order table . I have set the enforce
referential integrity and the checkboxes for both cascade update and cascade
delete related feilds functionality . When I enter data into the related
feild orderID in the order table the order details field is not updated as I
would expect . However when I delete the data entered into this feild in the
order table ( I manually entered the same data into this feild in the order
details table) the data was also deleted from the order details table. I
concluded that the delete cascade function seem to work fine. So why does the
cascade update not work ?

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John Vinson - 27 Dec 2004 20:49 GMT

> When I enter data into the related
>feild orderID in the order table the order details field is not updated as I
[quoted text clipped - 3 lines]
>concluded that the delete cascade function seem to work fine. So why does the
>cascade update not work ?

It's working correctly - it's your interpretation that is off!

A relationship does not, and SHOULD not, automagically create a new
empty placeholder record in the child table. A relationship *prevents*
you from adding "orphan" records; it does not create new records.

Normally one would use a Form bound to the order table, with a Subform
bound to the order-details table, with the OrderID as the master/child
link field. When there is data to be entered into the details table
(but not before!), the user would start entering data on the subform;
at that point the new record will be created. There is no need or
benefit to adding empty "placeholder" records.

John W. Vinson[MVP]

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Mike_iDbM - 27 Dec 2004 21:37 GMT

Yes , you are absolutely correct thank you for the precise clarification. I
tested your suggestion and the cascade update function works fine once the
record is
created and not before as you say empty placeholders are not a good thing.
This was my first question in this forum and I am truly impressed and
appreciative.

Thanks Again
Mike

> > When I enter data into the related
> >feild orderID in the order table the order details field is not updated as I
[quoted text clipped - 18 lines]
>
> John W. Vinson[MVP]

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