correct. I believe this is the same for all frameworks since this is not supported at the SQL level (ON DELETE CASCADE).
Massimo On Sep 6, 7:49 pm, Matthew <[email protected]> wrote: > It seems my question catalyzed quite a discussion! Thank you all for > weighing in. I certainly understand more of the underlying > architecture that makes these "sugary" things possible in web2py and > other frameworks. > > Just to clarify, Massimo; in order to use this type of "generic" in > web2py, I am essentially keeping a "master table" ('user', in your > example) referring to other records of different types. This means > that each object I create I have to make sure to insert a record into > the 'user' table. When that object is removed, I also have to remove > its reference from the 'user' table to keep it clean. Correct? > > On Sep 6, 7:10 pm, Yarko Tymciurak <[email protected]> wrote: > > > @Joe - > > > You are jumping ahead --- the point of appropriate abstractions is to > > specify what _kind of_ thing you are doinng, so in the future, when new uses > > arise, users do not need to adjust (e.g. site writers) - only the underlying > > implementation need change. > > > @Massimo - > > > while you "can do this" using integer, it misses the point of appropriate > > abstraction. It is not at all about what "web2py" knows; it is what the > > programmers using the framework know and read. (integers are > > implementation specific, and as an abstraction for this use are useless - > > integers are useful for MANY _kinds of_ things, and for this use, their use > > if obtuse in that it masks what intent and use is). > > > If you want web2py to "look" (to programmers) like it supports generic > > references (it does) then the language should represent that. Otherwise, you > > are relegated to implementation details and questions of "how do I do > > _this_ _kind of thing_ in this framework - you do not want to be > > replicating implementation details at every programmer - whenever possible, > > it should be self-evident; this is one of thse cases where that improvement > > could be made. > > > - Yarko > > > On Sun, Sep 6, 2009 at 5:43 PM, mdipierro <[email protected]> wrote: > > > > There are oranges and there are apples. > > > > oranges are arbitrary foreign keys. The problem here is not > > > implementing them in the DAL. this could be done in a couple of lines > > > of code. The problem is 1) is this good practice? I think no. 2) how > > > should SQLFORMs handle this? > > > > apples are "polymorphic references". You can do this using "integer". > > > I do not see the need for defining another keyword unless you want to > > > make web2py aware that this integer contains a polymorphic reference. > > > Assuming this were possible (and it is not in an easy way), what would > > > you like the DAL to do with it? > > > > Massimo > > > > On Sep 6, 5:02 pm, Joe Barnhart <[email protected]> wrote: > > > > OK, I'm confused. Are you suggesting that "reference generic" should be > > > an > > > > alias for "integer" or that it should be smarter and permit UUIDs and > > > other > > > > structures? Is this a beginning of a "foreign key" concept for web2py? > > > > That might have some pretty extensive usefulness... > > > > > On Sun, Sep 6, 2009 at 12:49 PM, Yarko Tymciurak <[email protected]> > > > wrote: > > > > > > On Sun, Sep 6, 2009 at 2:45 PM, Joe Barnhart <[email protected] > > > >wrote: > > > > > >> I am not against sugary goodness in general, but this seems like > > > something > > > > >> that might be better handled with education rather than overlaying > > > > >> the > > > name > > > > >> "integer" with "reference genric". (Besides, then what would you do > > > with > > > > >> people who wanted to use UUIDs for their "reference generics" instead > > > of > > > > >> integers?) > > > > > > ... that is my point - why educate on integers, when that's not good > > > > > education; hide the implementation into a logical abstraction > > > > > (generic > > > > > reference term just being borrowed from Matthew's post). > > > > > > Your point about UUIDs sounds more like an agrument _against_ teaching > > > > > about integers than anything else, to me at least... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py-users" 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/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
