Re: Many-to-Many inside same Entity
Re: Many-to-Many inside same Entity
- Subject: Re: Many-to-Many inside same Entity
- From: Robert Walker <email@hidden>
- Date: Tue, 7 Feb 2006 17:06:05 -0500
Amedeo,
What you have here is a design pattern known as a "Bill of
Material." It can be quite involved implementing a "Bill of
Material" and there are different types of these to consider. The
main two are "Engineering Bill of Material" and "Manufacturing Bill
of Material."
Here is a short non-technical explanation of a "Bill of Material:"
http://www.npd-solutions.com/bom.html
As you suspect this does require a "reflexive" many-to-many
relationship. It also requires a "recursive" validation to make sure
that no subassemblies ever contain the "root" product.
You will need an exposed join table (so no flattening of the many-to-
many can be used). At minimum the join table will need an "exposed"
attribute to indicate the quantity of each component part used in the
product being built.
Part <---->> ComponentAssembly <<---- Part
On Feb 7, 2006, at 6:31 AM, Amedeo Mantica wrote:
Hi, a question... how to implement this:
Products entity...
some product can be related to many other products...
then I need to join in many-to-many the same entity...
any suggestion?
thanks
Amedeo
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
40mac.com
This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden