This is probably off-topic; I hope someone can tell me where it should properly be raised. In a schema I have a Category table related m:m to itself via a Subcategory table, allowing the recursive construction of taxonomies of indeterminate depth. There is also a Thing table, and a ThingCategory table that allows things to be assigned any number of classifications. It is possible for categories to apply to a thing indirectly by implication of what might be described as taxonomic inheritance. (In fact the taxonomy is potentially a network rather than an hierarchy, so there can be multiple inheritance, but that is another matter.) I am somewhat at a loss as to how to model this arrangement even using EJB2, and I am looking for guidance, or at least constructive discussion. Should I attempt the resolution of applicable categories in a method of a stateless session bean or with some kind of entity bean? I doubt it can be expressed declaratively, since most flavours of SQL cannot tree-walk (recursively resolve self-joins) - this is the classic explosion-of-parts conundrum endlessly chewed over in the relational world. Perhaps there is already machinery to handle this situation. If so, I should be pleased to RTFM if someone would be so kind as to indicate which FM to R. If, as I suspect, the case is as yet unconsidered, then it would be well to work a general solution into some future release of EJB; such a thing would, I suspect, be profoundly useful, allowing straightforward and compact representation of the recursive classifications so common in the natural world. Peter Routtier-Wone --------------------------------------- One day, all this too shall parse. -- -------------------------------------------------------------- To subscribe: [EMAIL PROTECTED] To unsubscribe: [EMAIL PROTECTED] List Help?: [EMAIL PROTECTED]
