Hi

I have two tables Project And ProjectAssignment, a one-to-many mapping from Project to ProjectAssignment
Project
- ID
- Title
- StartDate
- EndDate

ProjectAssignment
- ID
- ProjectID
- IsProjectManager

I have to display all project with their project manager (there can be only one projectmanager for each project). The question is, can I map such a thing.

So If I load a project I would like to get all ProjectAssignments in a list, with the manager as wel (no problem here) and I want the projectManager of the project (ProjectAssignment where IsProjectManager = true) so I can ask to the project object
Project.ProjectManager
Is there any way to achieve this last option with hibernate ?

thanks

We need to do this as well. From what I understand, it can't be done through the mapping (I expected to be able to define a one-to-one property with a "where" attribute, but that attribute is not supported for one-to-one mappings). We haven't tried it yet, but I think you'll need to create an unmapped property in your class that simply loops through the mapped collection property to find the correct one. Unforuntately, this defeats lazy-loading on the collection ...

Of course, you can still get the project manager explictly through a query:



This is undesirable, though, if you'll have many queries where you want to refer to the project manager. It would be much cleaner if it could be done through the mapping so you could do



Almost all of our collection items have a property called IsPrimary, and there will be one and only one item where it's set to true. Most of our queries will want to select the primary collection item, so we'd like to be able to define them as one-to-ones in the mapping so all our queries are cleaner.