[hibernate-dev] Regarding Alex Bacon's "Major issue with Hibernate Filters" circa Sept 11, 2006...

I have a similar situation to what Alex Bacon described in his "Major issue with Hibernate Filters" thread in September, and I'm wondering if there was ever a palatable resolution. The basic notion is that I have an object graph consisting of relationships of varying multiplicity. For various reasons I wish to introduce "effective dates" into the database. The documented Filter example of Employee and Department pretty much illustrates the idea. Lets say that at any given time, an Employee belongs to one Department, and a Department has multiple employees (so Department has a one-to-many bidirectional relationship with Employee.) Employee contains a foreign key back to Department, which is the canonical way to represent one-to-many relationships in the database - by putting a foreign key on the "many" side. Over time, an employee can move between departments, so without considering time the relationship between Employee and Department is many-to-many. Note that I don't actually need a many-to-many join table here: Employee still contains an FK back to Department, and a given Employee ID now appears multiple times in the Employee table with non-overlapping "effective date" time intervals. At particular point in time, only ONE Employee row is effective. I only care about the relationships that exist at particular points in time. Therefore, I wish to apply a Filter that *I know* will always produce a one-to-many relationship between Department and Employee. Steve's comment suggests that this is a misapplication of "Filter" - because to assume that Filter will slice the one-to-many relationship (at a single point in time) out of the many-to-many relationship that is actually stored in the database would be using Filters to change multiplicity, and that is apparently NOT the intent. Fine: so forget Filters. Is there another way to get this same effect? I know one way: I can create views that reproduce the "full" object graph at each point in time that is of interest. Those views will have the correct one-to-many (or one-to-one) relationships in them. I could then map the views with Hibernate. The downside here is, I *also* need to map the "current time" of the real underlying tables, so that I can manipulate them to write updates. That means I need essentially two mappings of the same set of objects, which sounds like more work. The "Filter" concept seems so close to what I want... If Entity-level Filters are ALWAYS applied to generated SQL it seems like this would work, at least if I always enable the Filter before doing any operations involving timesliced entities. If autoenabled Filters were present (per ANN-433) it seems like the solution would be even sweeter. Has anyone had REAL experience using timeslicing (effective dates, etc) in the database and mapping the single-point-in-time results with Hibernate? I've seen this pattern in several databases in my career - although typically it seems to appear in warehouse environments more than in production databases..; -ed