On Dec 14, 11:10 pm, "Nicholas Orr" <[email protected]> wrote: > On Sat, Dec 13, 2008 at 5:40 AM, Dan Kubb (dkubb) <[email protected]> wrote: > > > > > Hi Nicholas, > > >> I have this data >http://files.nicholasorr.com/data.html > > > I don't mean to be rude, but looking at this data, this looks > > *exactly* like a homework assignment. I mean, the contrived data > > combined with the answers it's expected to satisfy, there's just no > > question in my mind. If this is homework, you're probably better off > > admitting that up-front. > > The contrived data is just simplified. > It isn't homework - I get how it appears like homework. > > > > > Also you're unlikely to find help in an online forum for such tasks > > unless you provide all the code examples you've done, including the > > exact code that didn't work. You should also try to explain why you > > thought each code example should have worked, and ask for specific > > help to explain where you went wrong. If you post your code on > > gist.github.com or pastie.org and provide the link in future emails > > you'll have better results. > > >> I'm not looking for complete models here, just the relationships. > >> I've done the models all ready > >> I also did the relationships that I thought would work. > >> They don't work. > > > As I mentioned to you in IRC, you're best approach to data modeling is > > to sit down with a pencil and paper and draw out the diagrams of how > > things relate. Writing the model code before figuring out the proper > > relations between the entities is likely the backwards approach when > > you're just learning. In fact I almost never write code without first > > sketching a rough outline of my entities, how they relate and the key > > data each entity contains. > > Yeap. I tried this one on and came up with something. I've implemented > most of it. > > http://gist.github.com/35835 > > What I'm having trouble with now is: > > how to get n rates associated with a rate_plan & a productlender > > I think I need another table that is just a group of rates - but that > is what the rate_plan table is suppose to be.. > > As a "user" you have a rate_plan. In this rate_plan is a product who > has a lender who has some rates/rate_modifiers. > There is one product with multiple lenders and the lender rates are > different to each other. > > As you can see the code is a lot more detailed then the simplification > I gave earlier and all I'm really looking for here is guidance on how > to link the different models together - thanks :)
Nicholas, the way I'm reading your problem description, it sounds as if a product lender can belong to multiple rate plans and each rate plan has multiple product lenders, i.e. these two things have a many to many relationship. Also, a specific rate and rate modifier seem to be associated with each particular combination of rate plan and product lender, not with a rate plan as indicated in your current design. If this is the case, I would suggest a 'has n :through => :some_through_resource' relationship between ProductLender and RatePlan. Conceivably, the rate and rate modifier properties could actually be attributes of the through model, but otherwise each could have a one to one or one to many relationship with the through model, depending on your requirements. I suspect the latter. Mark. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "DataMapper" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/datamapper?hl=en -~----------~----~----~----~------~----~------~--~---
