Hi Hugi, I have no idea if this will work, but try the following:
* in Cayenne Modeler, add companyNumber (company_number) as an attribute for Company. * Regenerate classes. * In Company.java, override the setCompanyNumber method to check for nulls. If non-null, call the super; if null, ignore it. On Mon, Oct 21, 2019 at 7:19 AM Hugi Thordarson <h...@karlmenn.is> wrote: > Hi all. > > I'm currently in the progress of cleaning up an older system and I have a > bit of a conundrum that I would love some input on. > > Almost all data in the DB belongs to/is related to a "Company" object. The > PK of that company object forms part of a compound PK for the other objects. > For example; here "Customer" and "Invoice" are related to "Company" on the > "company_number" attribute, "Invoice" has a related "Customer" joined on > "company_number" and "customer_number". > > Company > ------------------------ > * company_number (pk) > > Customer > ------------------------ > * company_number (pk) > * customer_number (pk > > Invoice > ------------------------ > * company_number (pk) > * invoice_number (pk) > * customer_number > > > Now, I've modeled all of this in Cayenne and it's been working very well > for years for reporting purposes. However, we're now moving the "writing" > part of the system to Cayenne as well, and that's caused a small problem. > > For the most part it works very well. An object will never change > companies once created, so if I set a "Customer" on an an "Invoice", it > doesn't have any undesired side effects, it's essentially just setting the > same company number again—no harm in that. > However, a problem occurs when I set an Invoice's customer to null. In > that case, Cayenne will nullify both the invoice's customer_number AND > company_number, which is obviously problematic. > > I'm now wondering how I can solve this problem, i.e. how can I set an > invoice's customer to "null" without blowing up the system. > > I'm open to "dirty" solutions since this is a temporary situation. The > Cayenne version of the system just has to work alongside an older system > for a couple of months, but once that's been closed, I have full control of > the DB and these tables will be getting their own shiny new unique PKs. > > About the only thing I don't want to do is expose the FKs and/or handle > relationships using manual fetching, since the relatiosnhips are already > modeled and I have thousands of lines of logic that depend on the modeled > relationships. > > Any ideas? > > Cheers, > - hugi
