Hibernate version:
3.1

I have a class called RecordStatus with the following
attributes




I have a legacy table called Lookup which has a foriegn key (LOOKUP_CAT_ID) into a LookupCategory table. The status and statusReason attributes above are represented as separate LookupCategory table entries with the statusDescription and statusReasonDescription attributes occurring in the Lookup table (with status as the foriegn key). An example of the Lookup table is as follows



One can have the same recordStatusReason for different recordStatus entries and they are maintained separately.

Each instance of the RecordStatus class only has one combination of status and statusReason but I'm not sure if and how this can be mapped? I can change or break up RecordStatus if necessary.

Any suggestions?
Thanks
Alan

First, it will be much easier to have RecordStatus defined like this:If you want RecordStatus to have getStatus(), getStatusDescription(), etc. methods, then do that using delegation.

I suggest forgetting about the status/statusReason combination constraint in the mapping, and just have two many-to-one relationships from RecordStatus to Lookup. Then enforce the constraints in business logic. This is the simpler and more maintainable solution.

It is possible to have hibernate do this for you, at least in Hibernate3+. It's a bit involved:

- Create StatusLookupImpl and StatusReasonLookupImpl classes: these won't be directly referenced in your app, just in your mapping. You'll be using the Lookup interface throughout your app (and these classes will implement it).

- Use the <subclass> element to describe StatusLookupImpl and StatusReasonLookupImpl as subclasses of LookupImpl (which also implements the Lookup interface).

- Use the where="" attribute in any classes that refer to Lookup objects (presumably, just the RecordStatus class) specify that a particular set uses just StatusLookupImpls or just StatusReasonLookupImpls.

Like I say, it's a bit involved, and definitely requires more work to maintain, hence the recommendation to enforce that constraint in java code. I use this solution in my own apps, though, and it is quite effective.

Thanks again. Another credit coming your way!

I assume the Lookup interface will specify the getter and setters for the Lookup table attributes?

Also, I'm not clear on the mapping file. Is it in the RecordStatus mapping file that the 2 subclasses (StatusLookupImpl and StatusReasonLookupImpl) be defined? The where attribute can only be specified on the class, so will it look like this:


I'm a bit confused

Regards
Alan

On re-reading your earlier posts, I find myself confused, because I can't find a reference to a RecordStatus table anywhere. It looks like you're hoping to map two rows from one table into one mapped object. I'll go on with my explanation assuming that there is a RecordStatus table somewhere, and it just hasn't been mentioned yet. If there really isn't a table with two associations to your Lookup table (one for status and one for statusReason), then I'm pretty sure that there's no way to map a RecordStatus object. Anyway...


The Lookup implementation class will specify those getters and setters. You don't have to provide a Lookup interface if you want the API user to use only RecordStatus: I'd probably recommend having a Lookup interface with at least the getters.


No, you use the LookupImpl class to be the parent of the two "real" impl classes. You could start with this mapping, then tailor it for your exact values:If you need to map a collection of Status or StatusReason objects, that's where the where attribute comes in: