B will help you filter your drop down of component package if you can only have in a package the same supertype component.
Difficults to say without concrete example. Richard On Thu, Sep 11, 2014 at 9:58 AM, Jan Beilicke <jan.beili...@gmail.com> wrote: > These are just sample names. In reality they are separate business/use > case entities sharing only the same supertype, they are not enumerated. > > Am Donnerstag, 11. September 2014 15:42:47 UTC+2 schrieb Richard: >> >> Why component_a, _b, _c... You will end up create new table all the >> time... >> >> Richard >> >> On Thu, Sep 11, 2014 at 7:04 AM, Jan Beilicke <jan.be...@gmail.com> >> wrote: >> >>> Hi everyone, >>> >>> I'm working on a web2py project which requires a complex relationship >>> model. I want to use a model that works well with web2py's DAL and I would >>> be glad if somebody could point me into the right direction. >>> >>> I created a small sample ER diagram to illustrate my problem, only the >>> important parts are displayed and the table names are generalized for >>> easier understanding. The database has a couple of tables (or business >>> objects), most of them are depending on some supertype, let's call it >>> 'component_type', the subtypes 'component_[a-z]'. >>> >>> The business case requires to create a component_package which contains >>> required components, but *all components in the package must be of the >>> same component_type.* >>> >>> Two possible variants are shown in the illustration: >>> >>> Variant A: The component_package contains the foreign keys of the >>> component tables. >>> Variant B: The package additionally contains the foreign key of the >>> component_type table. >>> >>> Which variant would you recommend and which one might work better with >>> DAL? Unfortunately, all the resources and database design documents I found >>> in the web were only explaining the general supertype/subtype relation. >>> >>> Thank you in advance and >>> kind regards, >>> >>> Jan >>> >>> >>> <https://lh3.googleusercontent.com/-zgZdMMjkmwg/VBF_6_5O2FI/AAAAAAAAAYc/PXyEaTB32iQ/s1600/relation_problem.png> >>> >>> -- >>> Resources: >>> - http://web2py.com >>> - http://web2py.com/book (Documentation) >>> - http://github.com/web2py/web2py (Source code) >>> - https://code.google.com/p/web2py/issues/list (Report Issues) >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "web2py-users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to web2py+un...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > Resources: > - http://web2py.com > - http://web2py.com/book (Documentation) > - http://github.com/web2py/web2py (Source code) > - https://code.google.com/p/web2py/issues/list (Report Issues) > --- > You received this message because you are subscribed to the Google Groups > "web2py-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to web2py+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
