Re: [xwiki-devs] mimic relational database one to many relations

Thanks Pascal that's very helpful! Now is there a way to dynamically include all the people when you view a page with a CompanyClass instance? Any clues on how to leverage a HQL query to display related people and companies?

On 18/12/2009, at 3:56 PM, Pascal Voitot [via XWiki] wrote: > Just for information, > you can "simulate" a ONE2MANY relation with dblists. > As far as I can remember (I don't have my XWiki in front of me): > you create a class CompanyClass with a field that you will manage by > yourself as a unique primary key. For example the property "name" of > the > company. Each company has a different name. > > Then you create a class PersonClass with a DBStringList property > called > "company" and in the form, you set XWikiClass to "CompanyClass" and > property > to "name" and you set the way to choose the company to "select". > > Then you create some CompanyClass Objects. > So when you create a new PersonClass Object, in the inline editor, you > should see a list with all the companies names you created. In fact, > XWiki > performs a HQL request to retrieve a list of the "name" properties > for all > CompanyClass objects. > > It is not a real DB relation as you can imagine in hibernate because > there > is no physical relationship between 2 table Person and Company. So > if a > Person has a company property set to a given value and then you > change this > Company object property "name", the Person is not aware about it and > will > keep the former name. > Anyway, this is quite practical in most cases. > > You can even manage multiple values with a separator. > I use it intensively on my side and I love it :) > > Pascal > > On Fri, Dec 18, 2009 at 10:49 AM, Helenc<[hidden email]> wrote: > >> >> Hi All, >> >> I would really like to be able to mimic one to many relations > through >> classes somehow? >> >> I noticed there have been a few posts about how one might go about > such a >> thing using dblists, it's not clear yet to me how I could > implement such a >> thing? I'm wondering if any demo application exist that might give > me more >> of a clue? >> >> Let's say I want to set up a simple one to many relationship between >> information about a company and then individuals who worked for that >> company. How would I go about such a thing? >> >> Do I setup a companyclass and a personsclass and then link them > somehow >> with >> the dblist? >> >> What's the best user interface setup for this too so it's easy for > users to >> enter company and people data? >> >> Are there any examples of HQL queries about how one would then > search to >> display individuals details along with elements of their companies > details? >> Referencing the relationship? >> >> Or is there another way to do this? Any pointers would be very much >> appreciated? >> >> Thanks >> Helen