From: | Thomas Pundt <mlists(at)rp-online(dot)de> |
---|---|
To: | pgsql-general(at)postgresql(dot)org, gongzhixiao(at)gmail(dot)com |
Subject: | Re: I have a select statement on the issue. |
Date: | 2007-11-28 08:31:49 |
Message-ID: | 200711280931.49677.mlists@rp-online.de |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Hi,
On Mittwoch, 28. November 2007, gongzhixiao(at)gmail(dot)com wrote:
| Step 4:Update Date
| update test set name='1111name' where code='1002'
Simplified, when you perform an update, PostgreSQL internally marks
the affected row as deleted and inserts a new row in the table. For details
look at the MVCC documentation, eg.
http://www.postgresql.org/docs/8.2/interactive/mvcc-intro.html
| Results:
| code name qty
| 1001 1001name 1
| 1003 1003name 3
| 1002 1111name 2
|
| Question:
| 1. Why the default output changes after I execute the update statement?
See above; output order is not guaranteed without order clause.
| 2. Qustion, sorting as main keys when query, how to do?
You mean: select * from test order by code ?
Ciao,
Thomas
--
Thomas Pundt <thomas(dot)pundt(at)rp-online(dot)de> ---- http://rp-online.de/ ----
From | Date | Subject | |
---|---|---|---|
Next Message | Greg Smith | 2007-11-28 08:51:54 | Re: Linux v.s. Mac OS-X Performance |
Previous Message | Rodrigo De León | 2007-11-28 08:26:53 | Re: I have a select statement on the issue. |