> "Christopher Kings-Lynne" <chriskl@familyhealth.com.au> writes:> > Am I misunderstanding how the mechanism works, or
isthis a big, noteasily> > solved, problem?>> The latter. Check the list archives for previous debates about this.>
It'snot real clear whether an inherited primary key should be expected> to be unique across the whole inheritance tree,
oronly unique per-table> (IIRC, plausible examples have been advanced for each case). If we want> uniqueness across
multipletables, it'll take considerable work to> create an index mechanism that'd enforce it.>IMHO current behaviour of
PostgreSQLwith inherited PK, FK, UNIQUE is
simplybug not only from object-oriented but even object-related point of view.
NowI can violate parent PK by inserting duplicate key in child!
Inherited tables should honours all constraints from parent. If I changesome constraint (seems only FK, but not PK or
UNIQUE)I should be able to
doit in more restrictive manner. For example, two base table is connected viaFK. I can change such FK in childs from
base1->base2to child1->child2 (orchild3) but not to child1->not_inherited_from_base2. CHECK, DEFAULT, NOTNULL are more
freeto changes, isn't it?
IMHO last message in doc/TODO.details/inheritance from Oliver Elphick is agood direction for implementing with
exceptionon more rectrictive child FKconstraint (p.3 of message).
As for me, I was pushed to rollback to scheme with no inheritance at all inmy project for now. So I'm very interesting
inimplementing of rightinheritance and I wanted to ask similar question in one of the lists in
nearfuture.
Regards,Dmitry
