Hi Farai, the categoryoptioncombo table is in fact very much part of the schema and has foreign keys from the categoryoptioncombos_categoryoptions and categorycombos_optioncombos join tables.
The point with category option combos is that we need a single foreign key in the datavalue table which links it to the category model - this because a data value can be linked to any number of category options and we cannot have a dynamic number of columns/foreign keys in the datavalue table to each of them. So the categoryoptioncombos represent a unique set of category options, allowing a single row in a single table to be linked to a data value. regards, Lars On Mon, Aug 19, 2013 at 1:03 AM, Farai Mutero <[email protected]> wrote: > Hi All > > I've been taking a closer look at the object model for Categories and > Category Combinations in Postgresql. While putting together the object > model I noticed that the *categoryoptioncombo* table* *is not dependent > on any other table in the database, yet contains critical values that are > also referenced in the *datavalue* table. > > My questions is, why *categoryoptioncombos? *Why link a datavalue table > row to a *categoryoptioncomboid* instead of a* dataelementcategoryoptionid > *? > > Regards > > -- > Farai Mutero > > > _______________________________________________ > Mailing list: https://launchpad.net/~dhis2-devs > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dhis2-devs > More help : https://help.launchpad.net/ListHelp > >
_______________________________________________ Mailing list: https://launchpad.net/~dhis2-devs Post to : [email protected] Unsubscribe : https://launchpad.net/~dhis2-devs More help : https://help.launchpad.net/ListHelp
