Re: surrogate vs natural primary keys

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От Seb
Тема Re: surrogate vs natural primary keys
Дата
Msg-id 87abe6vrgl.fsf@patagonia.sebmags.homelinux.org
обсуждение исходный текст
Ответ на surrogate vs natural primary keys  (Seb <spluque@gmail.com>)
Ответы Re: surrogate vs natural primary keys  ("Scott Marlowe" <scott.marlowe@gmail.com>)
Список pgsql-sql
On Tue, 16 Sep 2008 20:34:51 -0600,
"Scott Marlowe" <scott.marlowe@gmail.com> wrote:

[...]

> create table t2 (
>     d1 varchar(200),
>     d2 int8,
>     d3 varchar(1000),
>     foreign key t2_fk references t1(c1,c2) );

Thanks Scott, I guess you meant:

CREATE TABLE t2 (   d1 varchar(200),   d2 int8,   d3 varchar(1000),   PRIMARY KEY (d1, d2)   FOREIGN KEY (d1, d2)
REFERENCESt1(c1, c2) );
 

But this makes it difficult to work with t2 because it has 2 fields that
are the same as in t1.  Isn't it better to just use a surrogate key and
use a single field in t2, thereby avoiding repeating multiple pieces of
information?


Thanks,

-- 
Seb



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