Foreign keys: unexpected result from ALTER TABLE... ADD CONSTRAINT...

I cannot do this pair of table creations directly, because they are mutually
dependent.


create table purchased_job
(supplier    char(10)    not null                    references supplier (id) match full,specification
text,del_point   char(2)        not null                    references location (id) match full,import_licence    bool
     default 'f',import_duty    numeric(12,2),terms        char(3),deliv_clear    numeric(12,2),
 
foreign key (product, supplier) references product_supplier (product, 
supplier) match full
)inherits (job)
;



create table product_supplier
(product        char(10)        not null                    references purchased_job (product) match full,supplier
char(10)   not null                    references supplier (id) match full,
 
primary key (product, supplier)
)
;

so I omitted the foreign key specification from the creation of purchased_job
and tried to add it afterwards, but (after fixing a bug in gram.y) I found
that ALTER TABLE ... ADD CONSTRAINT is not yet implemented.  Is there, then, any
way to create this mutual dependency?

-- 
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver              PGP key from public servers; key
ID32B8FAA1                ========================================    "And, behold, I come quickly; and my reward is
withme,     to give every man according as his work shall be."                                  Revelation 22:12