On 16/01/2012 5:19pm, Bill Beal wrote:
Why not have a child model that differs from the one-to-one child model
in that the parent key is now a foreign key to the parent?  When another
child needs to replace the current one in the one-to-one relationship,
move the child to the second table where there is a many-to-one
relationship to the parent, then modify the one-to-one child record.  If
necessary, duplicate the current one-to-one record in the many-to-one
table.  Does this make sense?

I understand what you mean but it feels a bit yukky. Thinking about it some more maybe I need a 'hidden' field which gets updated on saving based on the existence of a more modern child.

Dunno.

Thanks

Mike



Bill Beal

On Mon, Jan 16, 2012 at 12:55 AM, Mike Dewhirst <mi...@dewhirst.com.au
<mailto:mi...@dewhirst.com.au>> wrote:

    I need a one-to-many to behave like a one-to-one.

    The parent instance of my model can only ever have one current child
    instance of another model. Multiple child instances have to exist
    and be kept for the historical record.

    The main benefit of one-to-one relationships is that they can be
    mapped together (in the Admin) as an extension of the parent.

    In a view I suppose I can use a manager to filter the children into
    a pseudo-one-to-one thingy but how do I do this in the Admin?

    Maybe sort them into date order and only show one? Is there a better
    way?

    Thanks for any help

    Mike

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