You are welcome! Richard
On Mon, Sep 15, 2014 at 3:45 PM, Jan Beilicke <[email protected]> wrote: > I chose approach B and it works fine. Thanks for mentioning drop downs. > > Kind regards, > > Jan > > Am Donnerstag, 11. September 2014 17:24:40 UTC+2 schrieb Richard: >> >> 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 <[email protected]> >> 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 <[email protected]> >>>> 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 [email protected]. >>>>> 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 [email protected]. >>> 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 [email protected]. > 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
