On Fri, 2006-27-10 at 12:37 -0400, Derek Atkins wrote: > Quoting Phil Longstaff <[EMAIL PROTECTED]>: > > > On Fri, 2006-27-10 at 11:58 -0400, Derek Atkins wrote: > > > >> I'm not sure what you mean by "cascade of DELETE operations". > >> I think we CAN depend on the DB supporting transactions, but it > >> might depend on what level of TXN support we want/need. > > > > With foreign keys, you can specify what should happen if a row in > > another table is changed when the first table refers to the second one. > > For example, we could set it up that since a transaction split refers to > > the account it is in (foreign key), if an account is deleted, all splits > > referring to that account are also deleted. Or, if the account GUID is > > changed, all splits referring to that account will have the foreign key > > GUID changed. > > Well, GnuCash already handles these cases. It wont let you delete an > account if there are splits in it. Also, GUIDs cannot change, so > that's never going to happen, either. > > I.e., gnucash itself already performs all these referential tests for > you; the DB just needs to be a pure data store. >
OK. I was just giving an example. A better one which comes to mind is with kvp frames. A kvp frame can be a number, string, date, list, or subframe. Each element of a list is in itself, a kvp frame, so there's a hierarchy here (and Josh mentioned how bad RDBMS's are with these). In this case, a slot can have a parent slot, either because it's a subframe or a member of a list. In this case, cascaded deletes help clean things up because the members of the list or subframes can be set to be automatically deleted when the parent is deleted. Now, if I want to delete a complete slot named X, I just delete the top level row in the table, and cascaded deletes take care of the others. Frequency specs are another example, because a compound fs can have fs's as children. Phil _______________________________________________ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
