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* Auto generate number in Postgres-9.1.
@ 2017-03-20 13:38 Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Re: Auto generate number in Postgres-9.1. Josh Berkus <josh@berkus.org>
0 siblings, 1 reply; 6+ messages in thread
From: Dinesh Chandra 12108 @ 2017-03-20 13:38 UTC (permalink / raw)
To: pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>; +Cc: pgsql-performance
Dear expert,
I have to add one column "ID" in postgres table which will generate Auto Increment<http://www.davidghedini.com/pg/entry/postgresql_auto_increment>ed number .
Example:
Suppose I have five records and if I insert 1 new record It should auto generate 6.
If I truncate the same table and then again insert rows should start with 1 in "ID" column.
Regards,
Dinesh Chandra
|Database administrator (Oracle/PostgreSQL)| Cyient Ltd. Noida.
________________________________
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* Re: Auto generate number in Postgres-9.1.
2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
@ 2017-03-20 13:43 ` Josh Berkus <josh@berkus.org>
2017-03-20 13:48 ` Re: Auto generate number in Postgres-9.1. Andreas Karlsson <andreas@proxel.se>
2017-03-20 13:50 ` Re: Auto generate number in Postgres-9.1. John Gorman <jgorman@eldocomp.com>
0 siblings, 2 replies; 6+ messages in thread
From: Josh Berkus @ 2017-03-20 13:43 UTC (permalink / raw)
To: Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>; pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>; +Cc: pgsql-performance
Dinesh,
> I have to add one column “ID” in postgres table which will generate
> Auto Increment
> <http://www.davidghedini.com/pg/entry/postgresql_auto_increment>ed number .
>
>
>
> Example:
>
> Suppose I have five records and if I insert 1 new record It should auto
> generate 6.
https://www.postgresql.org/docs/9.6/static/sql-createsequence.html
also SERIAL on this page:
https://www.postgresql.org/docs/9.6/static/datatype-numeric.html
>
> If I truncate the same table and then again insert rows should start
> with 1 in “ID” column.
That's not how it works, normally. I'd suggest adding an ON TRUNCATE
trigger to the table.
--
Josh Berkus
Containers & Databases Oh My!
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: Auto generate number in Postgres-9.1.
2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Re: Auto generate number in Postgres-9.1. Josh Berkus <josh@berkus.org>
@ 2017-03-20 13:48 ` Andreas Karlsson <andreas@proxel.se>
1 sibling, 0 replies; 6+ messages in thread
From: Andreas Karlsson @ 2017-03-20 13:48 UTC (permalink / raw)
To: Josh Berkus <josh@berkus.org>; Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>; pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>; +Cc: pgsql-performance
On 03/20/2017 02:43 PM, Josh Berkus wrote:
>> If I truncate the same table and then again insert rows should start
>> with 1 in “ID” column.
>
> That's not how it works, normally. I'd suggest adding an ON TRUNCATE
> trigger to the table.
Actually that may not be necessary as long as you make sure to use the
RESTART IDENTITY option when running TRUNCATE. I would argue that is a
cleaner solution than using triggers, if you can get away with it.
https://www.postgresql.org/docs/9.6/static/sql-truncate.html
Andreas
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: Auto generate number in Postgres-9.1.
2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Re: Auto generate number in Postgres-9.1. Josh Berkus <josh@berkus.org>
@ 2017-03-20 13:50 ` John Gorman <jgorman@eldocomp.com>
2017-03-20 14:08 ` Re: Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
1 sibling, 1 reply; 6+ messages in thread
From: John Gorman @ 2017-03-20 13:50 UTC (permalink / raw)
To: pgsql-performance; pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>
Sequences are stored as a separate object in PostgreSQL.
Here in this example table and you can see that rec_id is a sequence number and that the object name is: whiteboards_rec_id_seq
mydb=> \d whiteboards
Table "public.whiteboards"
Column | Type | Modifiers
---------------+-----------------------------+--------------------------------------------------------------
rec_id | integer | not null default nextval('whiteboards_rec_id_seq'::regclass)
board_name | character varying(24) | not null
board_content | text | not null
updatets | timestamp without time zone | default now()
Indexes:
"whiteboards_pkey" PRIMARY KEY, btree (rec_id)
Now I can display the whiteboards_rec_id_seq object
mydb=> \dS whiteboards_rec_id_seq
Sequence "public.whiteboards_rec_id_seq"
Column | Type | Value
---------------+---------+------------------------
sequence_name | name | whiteboards_rec_id_seq
last_value | bigint | 12
start_value | bigint | 1
increment_by | bigint | 1
max_value | bigint | 9223372036854775807
min_value | bigint | 1
cache_value | bigint | 1
log_cnt | bigint | 31
is_cycled | boolean | f
is_called | boolean | t
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Josh Berkus
Sent: Monday, March 20, 2017 6:43 AM
To: Dinesh Chandra 12108; pgsql-performance-owner@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Auto generate number in Postgres-9.1.
Dinesh,
> I have to add one column "ID" in postgres table which will generate
> Auto Increment
> <http://www.davidghedini.com/pg/entry/postgresql_auto_increment>ed number .
>
>
>
> Example:
>
> Suppose I have five records and if I insert 1 new record It should auto
> generate 6.
https://www.postgresql.org/docs/9.6/static/sql-createsequence.html
also SERIAL on this page:
https://www.postgresql.org/docs/9.6/static/datatype-numeric.html
>
> If I truncate the same table and then again insert rows should start
> with 1 in "ID" column.
That's not how it works, normally. I'd suggest adding an ON TRUNCATE
trigger to the table.
--
Josh Berkus
Containers & Databases Oh My!
--
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: Auto generate number in Postgres-9.1.
2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Re: Auto generate number in Postgres-9.1. Josh Berkus <josh@berkus.org>
2017-03-20 13:50 ` Re: Auto generate number in Postgres-9.1. John Gorman <jgorman@eldocomp.com>
@ 2017-03-20 14:08 ` Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 15:40 ` Re: Auto generate number in Postgres-9.1. Andreas Karlsson <andreas@proxel.se>
0 siblings, 1 reply; 6+ messages in thread
From: Dinesh Chandra 12108 @ 2017-03-20 14:08 UTC (permalink / raw)
To: John Gorman <jgorman@eldocomp.com>; +Cc: pgsql-performance; pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>
Hi,
Thanks for your immediate response!!!!
Its working fine when we insert a new row.
But on deletion it's not automatically re-adjusting the id's.
Do I need to create trigger for this??
Regards,
Dinesh Chandra
|Database administrator (Oracle/PostgreSQL)| Cyient Ltd. Noida.
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of John Gorman
Sent: 20 March, 2017 7:20 PM
To: pgsql-performance@postgresql.org; pgsql-performance-owner@postgresql.org
Subject: Re: [PERFORM] Auto generate number in Postgres-9.1.
Sequences are stored as a separate object in PostgreSQL.
Here in this example table and you can see that rec_id is a sequence number and that the object name is: whiteboards_rec_id_seq
mydb=> \d whiteboards
Table "public.whiteboards"
Column | Type | Modifiers
---------------+-----------------------------+--------------------------
---------------+-----------------------------+--------------------------
---------------+-----------------------------+----------
rec_id | integer | not null default nextval('whiteboards_rec_id_seq'::regclass)
board_name | character varying(24) | not null
board_content | text | not null
updatets | timestamp without time zone | default now()
Indexes:
"whiteboards_pkey" PRIMARY KEY, btree (rec_id)
Now I can display the whiteboards_rec_id_seq object
mydb=> \dS whiteboards_rec_id_seq
Sequence "public.whiteboards_rec_id_seq"
Column | Type | Value
---------------+---------+------------------------
sequence_name | name | whiteboards_rec_id_seq
last_value | bigint | 12
start_value | bigint | 1
increment_by | bigint | 1
max_value | bigint | 9223372036854775807
min_value | bigint | 1
cache_value | bigint | 1
log_cnt | bigint | 31
is_cycled | boolean | f
is_called | boolean | t
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Josh Berkus
Sent: Monday, March 20, 2017 6:43 AM
To: Dinesh Chandra 12108; pgsql-performance-owner@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Auto generate number in Postgres-9.1.
Dinesh,
> I have to add one column "ID" in postgres table which will generate
> Auto Increment
> <http://www.davidghedini.com/pg/entry/postgresql_auto_increment>ed number .
>
>
>
> Example:
>
> Suppose I have five records and if I insert 1 new record It should
> auto generate 6.
https://www.postgresql.org/docs/9.6/static/sql-createsequence.html
also SERIAL on this page:
https://www.postgresql.org/docs/9.6/static/datatype-numeric.html
>
> If I truncate the same table and then again insert rows should start
> with 1 in "ID" column.
That's not how it works, normally. I'd suggest adding an ON TRUNCATE trigger to the table.
--
Josh Berkus
Containers & Databases Oh My!
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
--
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This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. Check all attachments for viruses before opening them. All views or opinions presented in this e-mail are those of the author and may not reflect the opinion of Cyient or those of our affiliates.
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^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: Auto generate number in Postgres-9.1.
2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Re: Auto generate number in Postgres-9.1. Josh Berkus <josh@berkus.org>
2017-03-20 13:50 ` Re: Auto generate number in Postgres-9.1. John Gorman <jgorman@eldocomp.com>
2017-03-20 14:08 ` Re: Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
@ 2017-03-20 15:40 ` Andreas Karlsson <andreas@proxel.se>
0 siblings, 0 replies; 6+ messages in thread
From: Andreas Karlsson @ 2017-03-20 15:40 UTC (permalink / raw)
To: Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>; John Gorman <jgorman@eldocomp.com>; +Cc: pgsql-performance; pgsql-performance-owner@postgresql.org <pgsql-performance-owner@postgresql.org>
On 03/20/2017 03:08 PM, Dinesh Chandra 12108 wrote:
> But on deletion it's not automatically re-adjusting the id's.
>
> Do I need to create trigger for this??
It is possible to do but I advice against adjusting the IDs on DELETE
due to to do so safely would require locking the entire table in the
trigger.
Note that serial columns will also get holes on ROLLBACK. In general I
think the right thing to do is accept that your ID columns can get a bit
ugly.
For example:
CREATE TABLE t (id serial);
INSERT INTO t DEFAULT VALUES;
BEGIN;
INSERT INTO t DEFAULT VALUES;
ROLLBACK;
INSERT INTO t DEFAULT VALUES;
Gives us the following data in the table:
id
----
1
3
(2 rows)
Andreas
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2017-03-20 13:38 Auto generate number in Postgres-9.1. Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 13:43 ` Josh Berkus <josh@berkus.org>
2017-03-20 13:48 ` Andreas Karlsson <andreas@proxel.se>
2017-03-20 13:50 ` John Gorman <jgorman@eldocomp.com>
2017-03-20 14:08 ` Dinesh Chandra 12108 <Dinesh.Chandra@cyient.com>
2017-03-20 15:40 ` Andreas Karlsson <andreas@proxel.se>
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