On Fri, 6 Feb 2004, Gus Heck wrote: > Tried this but I am having issues.... > > I have an person object that holds a collection of ContactInfo. People > may be contacted at more than one place... etc. The contact info objects > are perfectly happy not knowing who they contact (they have no reference > to Person). This is an 1:n mapping, but the n contacts have no > dependancy on the 1 person. The xdoclet module seems to require that the > ContactInfo's all know about the Person's. This seems like a silly > requirement. > > From the ojbdoclet documentation: > > > foreignkey > > Contains one or more foreign key field or columns (separated by commas). > > If the collection implements an 1:n association, then this attribute > specifies the fields in the element type that implement the association > on the element side. Note that these fields are required to have the > ojb.field > > From my class > > /** > * @ojb.field > * @ojb.collection auto-retrieve="true" > * auto-update="false" > * auto-delete="false" > */ > Collection ContactsCollection; > > > The error: > > Generating repository_user.xml. > (XDocletMain.start 53 ) Running XDoclet failed. > (XDocletMain.start 54 ) <<No foreign keys > specified for collection ContactsCollection in type > org.cs101.fdb.impl.jdo.PersonBase.>> > build.xml [323] XDoclet failed. > at xdoclet.DocletTask.start(DocletTask.java:461) > at xjavadoc.ant.XJavadocTask.execute(XJavadocTask.java:95) > at > org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:166) > at org.apache.tools.ant.Task.perform(Task.java:319) > at org.apache.tools.ant.Target.execute(Target.java:309) > (the trace is about 30 miles long... I'll post it if it helps). > > How do I get around this? or am I forced to put in useless, backreference?
The reference from the element object to the object with the collection is not at all useless. It is how OJB actually implements the 1:n association (it stores the primarykey of the object with the collection). So basically you put in a field into the element type of the same type as the primarykey. There is a way to avoid this, however, by using an indirection table (as a 1:n association is a m:n association with an implicit constraint). Here you have the foreignkeys in a separate table referencing the primarykeys of the two ends of the association. BTW, when you use a collection type (as opposed to an array), you have to specify the element type, as well (using element-class-ref). Tom --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
