Ted
I'm no expert on inheritance, but typically the setup should be
Contact (Parent class) with a idContactType, marked as Abstract
ContactType (1, Employee; 2, Vendor; 3, Media)
Employee (Parent = Contact, Qualifier idContactType = 1)
VendorContact (Parent = Contact, Qualifier idContactType = 2)
MediaContact (Parent = Contact, Qualifier idContactType = 3)
Then from your
Company EO your relationship would be to Employee EO.
Your fetches would be
vendors = VendorContact.fetchVendorContact(ed,
VendorContact.SOME_INTERESTING.eq(someValue), null);
The type qualifier would be taken care of for you...
Paul
On Nov 19, 2011, at 9:00 AM, Theodore Petrosky wrote:
> I am learning about subclassing EOs.
>
> I have an entity; Contact
>
> and three subclasses Employee, VendorContact, MediaContact
>
> the qualifiers are: isEmployee (bool) isVendorContact (bool)
> isMediaContact (bool)
>
> ie:
> isEmployee <> 0
> isVendorContact <> 0
> isMediaContact <> 0
>
> testbed=# select * from t_contact;
> c_first_name | c_last_name | id | c_is_vendor_contact | c_is_media_contact |
> c_is_employee
> --------------+-------------+----+---------------------+--------------------+---------------
> Ted | Petrosky | 1 | t | t | f
> Bill | Simpson | 2 | t | t | t
> Harold | Wall | 3 | f | t | f
>
> so I set up a test page simple with ordered lists wrapped in WOReps
>
> and queried the backend to populate the NSArrays:
>
> theEC = ERXEC.newEditingContext();
>
> vendors = VendorContact.fetchVendorContacts(theEC,
> VendorContact.IS_VENDOR_CONTACT.eq(true), null);
> employees = CompanyEmployee.fetchCompanyEmployees(theEC,
> CompanyEmployee.IS_EMPLOYEE.eq(true), null);
> mediaContacts = MediaContact.fetchMediaContacts(theEC,
> MediaContact.IS_MEDIA_CONTACT.eq(true), null);
>
> System.out.println("Media List " + mediaContacts);
> System.out.println("Employees List " + employees);
> System.out.println("Vendor List " + vendors);
>
> After I ran my app it barfed at me:
>
> Error: java.lang.IllegalArgumentException: While trying to set the
> field "anEmployee" on an object of type com.eltek.components.Main we expected
> a com.eltek.model.CompanyEmployee but received a
> com.eltek.model.VendorContact with a value of <com.eltek.model.VendorContact
> pk:"1">. This often happens if you forget to use a formatter.
>
> Now I understand that I can not fetch these entities in a single EC as any
> contact could be a member of any or all subclasses.
>
> Did I miss something (a property maybe [since everything is a property]) or
> must I use multiple ECs in this case? Obviously, that was my solution, set up
> a different EC for each subclass. Then all is well (but is it?).
>
> Ted
>
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