Hi,
On Sep 29, 2008, at 4:50 PM, Matt S Trout wrote:
On Sun, Sep 28, 2008 at 05:56:11PM +0100, Oliver Gorwits wrote:
Ideally, DBIC would instead populate the relationship_info details
after someone has set up __PACKAGE__->many_to_many(...). That would
avoid this guesswork.
That would make no sense at all since many-to-many is NOT A
RELATIONSHIP.
I've been in this list for some years now that I've seen this phrase
written several times.
<pedantic>
If I recall correctly my time at CS department where I was forced to
read the relational model (not the -for-dummies version that is SQL
today. but the true horrid version), many-to-many was in fact a
relationship.
The classical link-table that we came to love/hate is in fact an
"implementation decision" in the sense that current SQL servers don't
have native support for many-to-many (in fact the SQL language is the
one who does not support it), so we hacked around it.
It was expected that implementations of the relation model would allow
you do declare such relationship and it would just work. I'm assuming
that the pragmatic engineers of those implementation would in fact
create a link table, only one hidden to you.
In practice, I don't believe anybody did in the end.
</pedantic>
Having said that, it is trivial to use your own base class for your
sources in a way that you can catch many-to-many declarations and
cache the result somewhere private (your own version of
relationship_info()).
I say that this is possible because I have code running in production
that does exactly that: creates a parallel relationship_info(), and
implements a similar recursive update/create/delete data-driven
operation, including many-to-many relationships.
The current, tested (in the sense that it has tests) and documented
version is not available. I don't have permission (yet) to release it.
Best regards,
--
Pedro Melo
Blog: http://www.simplicidade.org/notes/
XMPP ID: [EMAIL PROTECTED]
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