Re: Self-referential records - Mailing list pgsql-general

From Andreas Kretschmer
Subject Re: Self-referential records
Date
Msg-id 20100124145114.GA9660@tux
Whole thread Raw
In response to Self-referential records  (Ovid <curtis_ovid_poe@yahoo.com>)
Responses Re: Self-referential records  (Peter Geoghegan <peter.geoghegan86@gmail.com>)
List pgsql-general
Xi Shen <davidshen84@googlemail.com> wrote:

> > To handle that you can set the constzraint deferrable, initially
> > deferred:
> >
> > test=# CREATE TABLE refers ( id SERIAL  PRIMARY KEY, name VARCHAR(255) NOT NULL, parent_id INTEGER NOT NULL,
FOREIGNKEY (parent_id) REFERENCES refers(id) deferrable initially deferred); 
> > NOTICE:  CREATE TABLE will create implicit sequence "refers_id_seq" for serial column "refers.id"
> > NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "refers_pkey" for table "refers"
> > CREATE TABLE
> > Zeit: 25,599 ms
> > test=*# insert into refers (name, parent_id) values ('xxx',0);
> > INSERT 0 1
> > Zeit: 0,662 ms
>
> to Andreas,
>
> this 'deferrable' thing is really cool. but i have a question. at this
> point, where i insert this text, if i select the refers table, what
> would the parent_id looks like?

0, as i inserted:

test=*# insert into refers (name, parent_id) values ('xxx',0);
INSERT 0 1
Zeit: 0,636 ms
test=*# select * from refers;
 id | name | parent_id
----+------+-----------
  1 | xxx  |         0
(1 Zeile)




Andreas
--
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