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* Best way to change values of a primary key referenced by many tables
@ 2020-10-21 20:27 Andreas Joseph Krogh <andreas@visena.com>
0 siblings, 1 reply; 3+ messages in thread
From: Andreas Joseph Krogh @ 2020-10-21 20:27 UTC (permalink / raw)
To: pgsql-sql@lists.postgresql.org
Hi.
I'm looking for the easiest way to change the vaules of a PK of a table
(my_user), which is referenced by many FKs, with the minimum effort.
Here's an example-schema:
CREATE TABLE my_user ( id BIGSERIAL PRIMARY KEY, username VARCHAR NOT NULL
UNIQUE); CREATE TABLE my_person ( entity_id BIGSERIAL PRIMARY KEY, user_id
BIGINT REFERENCESmy_user (id), name VARCHAR NOT NULL ); CREATE TABLE my_project
(entity_id BIGINT PRIMARY KEY, name VARCHAR NOT NULL, created_by BIGINT NOT
NULL REFERENCESmy_user (id) );
CREATE TABLE my_company ( entity_id BIGINT PRIMARY KEY, name VARCHAR NOT NULL,
created_byBIGINT NOT NULL REFERENCES my_user (id) DEFERRABLE INITIALLY DEFERRED
); CREATE TABLE my_product ( entity_id BIGINT PRIMARY KEY, name VARCHAR NOT NULL
,created_by BIGINT NOT NULL REFERENCES my_user (id) ON DELETE CASCADE );
Now - I want to refactor so that my_user.id has the same value as my_person.
entity_id
Updating the value of my_user.id sounds simple, but how do I do that, and
update all other tables pointing to it with this new value, with as little
effort as possible, ie. don't have to ALTER/UPDATE every table having an FK to
my_user.id?
Not that some FKs are DEFERRABLE, others have "ON DELETE", and the requirement
is to not mess with that.
So - I'm basically looking for (I think) a way to add "ON UPDATE CASCADE" to
all columns referencing it, update the values and then removing all "ON UPDATE
CASCADE" on the referencing columns.
Appreciate suggestions, thanks.
--
Andreas Joseph Krogh
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Best way to change values of a primary key referenced by many tables
@ 2020-10-21 21:25 David G. Johnston <david.g.johnston@gmail.com>
parent: Andreas Joseph Krogh <andreas@visena.com>
0 siblings, 1 reply; 3+ messages in thread
From: David G. Johnston @ 2020-10-21 21:25 UTC (permalink / raw)
To: Andreas Joseph Krogh <andreas@visena.com>; +Cc: pgsql-sql <pgsql-sql@lists.postgresql.org>
On Wed, Oct 21, 2020 at 1:27 PM Andreas Joseph Krogh <andreas@visena.com>
wrote:
> Now - I want to refactor so that my_user.id has the same value as
> my_person.entity_id
>
> Updating the value of my_user.id sounds simple, but how do I do that, and
> update all other tables pointing to it with this new value, with as little
> effort as possible, ie. don't have to ALTER/UPDATE every table having an FK
> to my_user.id?
>
Given those constraints I'd suggest that your problem has no solution.
> Not that some FKs are DEFERRABLE, others have "ON DELETE", and the
> requirement is to not mess with that.
>
> So - I'm basically looking for (I think) a way to add "ON UPDATE CASCADE"
> to all columns referencing it, update the values and then removing all "ON
> UPDATE CASCADE" on the referencing columns.
>
While ALTER TABLE can alter a FK constraint it only can change the
deferrability property, not the trigger properties.
> Appreciate suggestions, thanks.
>
>
Say no.
David J.
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Best way to change values of a primary key referenced by many tables
@ 2020-10-21 22:11 Iuri Sampaio <iuri.sampaio@gmail.com>
parent: David G. Johnston <david.g.johnston@gmail.com>
0 siblings, 0 replies; 3+ messages in thread
From: Iuri Sampaio @ 2020-10-21 22:11 UTC (permalink / raw)
To: David G. Johnston <david.g.johnston@gmail.com>; Andreas Joseph Krogh <andreas@visena.com>; pgsql-sql <pgsql-sql@lists.postgresql.org>
Andreas,
if there’s a chance to redesign your datamodel from scratch, I’d go benchmarking one of the best Framework I’ve ever seen, for PostgreSQL object datamodel designing. OpenACS / Prject-Open
http://www.project-open.com/en/list-data-model <http://www.project-open.com/en/list-data-model;
I’d recreate the datamodel following the references available here
http://www.project-open.com/en/list-data-model <http://www.project-open.com/en/list-data-model;
For object design:
https://openacs.org/doc/object-system-design <https://openacs.org/doc/object-system-design;
This datamodel is based on OpenACS, a robust and high scalable community based system
https://openacs.org <https://openacs.org/;
Best wishes,
I
> On Rab. I 5, 1442 AH, at 18:25, David G. Johnston <david.g.johnston@gmail.com> wrote:
>
> On Wed, Oct 21, 2020 at 1:27 PM Andreas Joseph Krogh <andreas@visena.com <mailto:andreas@visena.com>> wrote:
> Now - I want to refactor so that my_user.id has the same value as my_person.entity_id
>
> Updating the value of my_user.id sounds simple, but how do I do that, and update all other tables pointing to it with this new value, with as little effort as possible, ie. don't have to ALTER/UPDATE every table having an FK to my_user.id?
>
> Given those constraints I'd suggest that your problem has no solution.
>
>
> Not that some FKs are DEFERRABLE, others have "ON DELETE", and the requirement is to not mess with that.
>
> So - I'm basically looking for (I think) a way to add "ON UPDATE CASCADE" to all columns referencing it, update the values and then removing all "ON UPDATE CASCADE" on the referencing columns.
>
> While ALTER TABLE can alter a FK constraint it only can change the deferrability property, not the trigger properties.
>
>
> Appreciate suggestions, thanks.
>
>
> Say no.
>
> David J.
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^ permalink raw reply [nested|flat] 3+ messages in thread
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2020-10-21 20:27 Best way to change values of a primary key referenced by many tables Andreas Joseph Krogh <andreas@visena.com>
2020-10-21 21:25 ` David G. Johnston <david.g.johnston@gmail.com>
2020-10-21 22:11 ` Iuri Sampaio <iuri.sampaio@gmail.com>
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