[GSoC] migration

[Bradley Giesbrecht]

> On Aug 10, 2017, at 3:49 PM, Joshua Root <jmr at macports.org> wrote:
> 
> On 2017-8-11 03:41 , Bradley Giesbrecht wrote:
>> I think Josh is referring to 3NF normalization (third normal form). I don’t think this use case warrants this complexity. I think it is fine for two snapshot id’s to reference the same port+variant combination. When a snapshot id is deleted, cascade delete.
> 
> Again I'm not sure how this differs from what I wrote. A snapshot contains any number of ports, and a port can be in any number of snapshots.

That does not make it a many-to-many. If the port was only in the ports table one time and you had a joining table joining that one port to many snapshots then you would have a many-to-many. But we are going to have the same port in the ports table for each snapshot so each row in the ports table belongs to only one snapshot, not many-to-many.


Regards,
Bradley Giesbrecht (pixilla)