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Re: Add new column

From: Guido Barosio <gbarosio(at)gmail(dot)com>
To: "Goulet, Dick" <DGoulet(at)vicr(dot)com>
Cc: Rafal Kedziorski <rafcio(at)polonium(dot)de>, pgsql-admin(at)postgresql(dot)org
Subject: Re: Add new column
Date: 2005-07-20 22:04:10
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-admin
Once ago I had a similar problem. 
The developers team requested about creating a new column, and the placement
was important. Thus, changing the app code was too expensive. A bad habit, 
was my reply, 
but as expected I had to found a solution for the problem.
 Create a view and rename the table, it will add a overhead, but it sort 
my problem. 
 (...and they didn't notice ;) )

 On 7/20/05, Goulet, Dick <DGoulet(at)vicr(dot)com> wrote: 
> Then drop and rebuild the table. Otherwise add it onto the end, which I
> believe is ANSI SQL expected behavior and forget about it. Where the
> column is in the table is less important than where you place it in the
> select statement. The only other time I can see column placement as
> being important is if it's part of the primary key, but even then I've
> had no problems with adding to the end of the table.
> -----Original Message-----
> From: pgsql-admin-owner(at)postgresql(dot)org
> [mailto:pgsql-admin-owner(at)postgresql(dot)org] On Behalf Of Rafal Kedziorski
> Sent: Wednesday, July 20, 2005 4:49 AM
> To: pgsql-admin(at)postgresql(dot)org
> Subject: [ADMIN] Add new column
> Hi,
> I wan't add new column to this table:
> CREATE SEQUENCE abo_product_2_user_seq;
> CREATE TABLE abo_product_2_user (
> abo_product_2_user_id BIGINT NOT NULL DEFAULT
> NEXTVAL('abo_product_2_user_seq'),
> abo_product_id SMALLINT NOT NULL,
> user_id BIGINT NOT NULL,
> valid_from TIMESTAMP NOT NULL,
> valid_to TIMESTAMP,
> debit_entry VARCHAR(12) NOT NULL,
> --
> PRIMARY KEY (abo_product_2_user_id),
> --INDEX (abo_product_id),
> --INDEX (user_id),
> FOREIGN KEY (abo_product_id)
> REFERENCES abo_product (abo_product_id),
> FOREIGN KEY (user_id)
> REFERENCES users (user_id)
> );
> But PostgreSQL 8.0.3 adds the new column at the end. I want add this
> new column between user_id and valid_from.
> Best Regards,
> Rafal
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match

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optimization algorithm is generally a good way to achieve less
performance, not more" - Tom Lane.

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