Back to School with GORM - Many-to-Many Improvements

This is a past event

15 people went

Location visible to members


Joe Little (systems architect at Stanford) will present details about GORM, common solutions or workarounds for many-to-many relationships and the problems those present when used extensively.

Meet at 6.15pm. Presentation from 6.45pm - 7.45pm. Hang out afterwards.

The Problem

Faculty, Company, and Project [or Faculty, Company and Course]

Given that each Faculty has many projects, and Company has many projects. A Project can have more than one Faculty, and perhaps even more than one Company.

Who is the owner in this case? In GORM/Hibernate, all hasMany and especially many-to-many relations require an owning side. And deleting a Faculty shouldn't cascade to those projects, and vice versa.

Its also important to be able to have finder methods that work without the need for HQL. Criteria isn't all that bad, but why can't we do :
Project.findAllByFacultyAndCompany(faculty, company) ?

Solutions & Best Practices

The purpose of this meetup will be to present some common solutions or workarounds to this problem, such as are used in the Grails community.

Also, given that Grails/GORM 2.0 development is underway can we get this to a state where it is presentable to the core team, or possibly escalate a JIRA for this kind of feature in the near future?


Joe Little of Stanford University will be presenting with sample code from the community.