Re: help with nested set

On Apr 13, 9:27 am, paul c <toledobythe..._at_oohay.ac> wrote:
> lawpoop wrote:
>
> ...
>
> > Suppose I had this adjacency list:
>
> > id  client_id parent_id level
> > 1       1        NULL      Corporate
> > 2       1          1       Franchise 1
> > 4       1          1       Eastern Region
> > 5       1          4       New York District
> > ...
>
> Can't comment on product techniques but if this were a 'table', I'd
> wonder how a client can be its own parent.  I would have thought some
> constraint would prevent that.

Are you asking why all of these example rows have a value for the client_id? Are you saying it should look like this? :

id client_id parent_id level

1       1        NULL      Corporate
2      NULL       1       Franchise 1
4      NULL       1       Eastern Region
5      NULL       4       New York District

MySQL check constraints are somewhat limited; what would you suggest? Received on Mon Apr 13 2009 - 18:53:02 CEST