Cayenne supports EJBQL[1] and SQLTemplate[2] for this sort of thing. Not sure if Cayenne is 100% EJBQL compliant though?
But if all else fails fallback to SQLTemplate :) kind regards Bob [1]: https://cayenne.apache.org/docs/4.1/cayenne-guide/#ejbql [2]: https://cayenne.apache.org/docs/4.1/cayenne-guide/#sqltemplate On Tue, Aug 14, 2018 at 10:11 PM Tony Giaccone <tgiacc...@gmail.com> wrote: > I have an object that contains a to many relationship to potentially 100's > of thousands of objects. I read in a file and generate this relationship > based on the contents of that file. > > Imagine that after the relationship has been created, we realize that the > file contained errors and we want to recreate this relationship by reading > a new file that describes the complete set of entries in the relationship. > > Note, I don't want to delete the objects that make up the toMany > relationship. I just want to break the relationship between the source and > the many destination objects. > > My first thought is to null out the relationship, There's a foreign key in > the dependent object that describes its parent. So first step is set all > those values to null. > > Then I'll iterate through the list, recreating the relationship based on > the contents of the file. > > This is the brute force approach that solves the problem of what do I do > about entries in the old list that aren't in the new list. > > My question is this. Is there an easy way to break that connection. I > looked didn't see anything. > > Essentially want to do this: > > Assume two tables t1,t2. > There is a to-Many relationship between t1 and t2. The foreign key column > in table t2 is fkt1. > > update t2 set fkt1 = null where fkt1 = %A_VALUE; > > This is kind of counter to the Cayenne way of doing things, but it's a > large number of objects and I can't see the point in iterating through them > on by one to delete the relationship. > > > > > Tony >
