Thread: Inheritance and Foreign Keys
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?
Thanks
--
Nelio Alves Pereira Filho
IFX Networks - www.ifx.com.br
+55 11 3365-5863
nelio@ifx.com.br
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