Inheritance and Foreign Keys

Nelio Alves Pereira Filho wrote:

Here's my situation: I have the following relation

table A -----<>------ table B
1:N

I created the two tables, and a foreign key from A into B. Now I want to
create other tables that inherit from B, but I want that the relation
exists for all of them. For that, I created another table, C, that had
just one field and inherited from B. No errors showed up, but it didn't
complain when I inserted some data into C without the corresponding one
in A!!

Is it possible to do what I intended?

Unfortunately not. Inheritance is not properly thought out; at present
it allows fields to be duplicated and records selected from an inheritance
hierarchy, but this is relatively useless because constraints are not
inherited and indexes are not shared.

--
Oliver Elphick Oliver.Elphick@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
PGP: 1024R/32B8FAA1: 97 EA 1D 47 72 3F 28 47 6B 7E 39 CC 56 E4 C1 47
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
"But because of his great love for us, God, who is rich
in mercy, made us alive with Christ even when we were
dead in transgressions-it is by grace you have been
saved." Ephesians 2:4,5

Is it planned to include these features to class inheritance?

Nelio

Oliver Elphick wrote:

Nelio Alves Pereira Filho wrote:

Here's my situation: I have the following relation

table A -----<>------ table B
1:N

I created the two tables, and a foreign key from A into B. Now I want to
create other tables that inherit from B, but I want that the relation
exists for all of them. For that, I created another table, C, that had
just one field and inherited from B. No errors showed up, but it didn't
complain when I inserted some data into C without the corresponding one
in A!!

Is it possible to do what I intended?

Unfortunately not. Inheritance is not properly thought out; at present
it allows fields to be duplicated and records selected from an inheritance
hierarchy, but this is relatively useless because constraints are not
inherited and indexes are not shared.

--
Oliver Elphick Oliver.Elphick@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
PGP: 1024R/32B8FAA1: 97 EA 1D 47 72 3F 28 47 6B 7E 39 CC 56 E4 C1 47
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
"But because of his great love for us, God, who is rich
in mercy, made us alive with Christ even when we were
dead in transgressions-it is by grace you have been
saved." Ephesians 2:4,5

--
Nelio Alves Pereira Filho
IFX Networks - www.ifx.com.br
+55 11 3365-5863
nelio@ifx.com.br