agora inbox for postgres@postgres.berkeley.edu  

help / color / mirror / Atom feed

From: Giles Nelson <Giles.Nelson@cl.cam.ac.uk>
To: postgres@postgres.Berkeley.EDU
Subject: time travel
Date: Wed, 09 Nov 1994 13:57:59 +0000
Message-ID: <"swan.cl.cam.:198030:941109135811"@cl.cam.ac.uk> (raw)

Hello all.

I have a query about the facilities POSTGRES gives for historical databases,
what the user manual terms as `time travel'.

Classes can be created to be archival or not. The default is not. Therefore
after instances are deleted, purged and the database vacuumed those instances
will have been physically deleted.

Alternatively a class may be defined as archival. Even after vacuuming
therefore deleted instances are still accessible.

The time stamp that POSTGRES appears to attach to each instance is what is
often termed `database time', that is the time at which the instance was
actually inserted into the database.

I would like to use the built-in facilities that POSTGRES has for time travel
but I wish to time stamp each instance with an `event time', that is the time
which is associated with the instance itself, such as a birth date.

My impression is that this is not possible and I will have to use a time
attribute within a relation. However I wondered if anyone else had experience
of doing directly and therefore retaining the use of built-in facilities.

Giles Nelson.

==============================================================================
   To add/remove yourself to/from the POSTGRES mailing list: send mail with 
   the subject line ADD or DEL to "postgres-request@postgres.Berkeley.EDU"

   If this fails, send mail to "post_questions@postgres.Berkeley.EDU" and
   a human will deal with it.  DO NOT post to the "postgres" mailing list.
==============================================================================

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: postgres@postgres.berkeley.edu
  Cc: Giles.Nelson@cl.cam.ac.uk
  Subject: Re: time travel
  In-Reply-To: <"swan.cl.cam.:198030:941109135811"@cl.cam.ac.uk>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox