On Mié 05 Dic 2001 18:03, Aasmund Midttun Godal wrote:
> I am not sure what you are trying to do, but if you have a tree structure
> you will have to use an id column e.g.:
>
> CREATE TABLE domain (
> id SERIAL PRIMARY KEY,
> name TEXT CHECK (lower(name) ~ '[a-z0-9]([a-z0-9-]*[a-z0-9])?',
> parent INTEGER REFERENCES domain,
> UNIQUE (parent, name)
> );
>
>
> If you do not have a tree structure, I would recommend using a natural
> primary key in stead of serializing it. Bear in mind though - you should
> always have a primary key. I would also recommend creating a couple of
> functions to build a fully qualified domain name from the id.
No, it's not a tree structure.
The question is why not serialize it?
I vote for not serializing it because when I get the data from the database,
I don't have to join the 2 tables (the domain name is on both tables).
CREATE TABLE domain (name CHAR(30) PRIMARY KEY
);
CREATE TABLE nodes (id SERIAL,name CHAR(30),domain CHAR(30) REFERENCES domain ("name")
);
This is a better approach then putting a SERIAL value to the domain table and
making nodes.domain reference to that SERIAL? Why?
Saludos... :-)
--
Porqué usar una base de datos relacional cualquiera,
si podés usar PostgreSQL?
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Martín Marqués | mmarques@unl.edu.ar
Programador, Administrador, DBA | Centro de Telematica Universidad Nacional
del Litoral
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