[postgis-users] Data Versioning?

[Gary Sherman]

ArcSDE implements versioning at the server (read SDE software)  level.
The database tier has no inherent "versioning" capability, regardless of
whether it is running on Oracle, Informix or Brand X. Versioning is
implemented using "delta" tables that track changes (adds and deletes)
across versions. There are a slew of other tables (what I call "meta"
tables) that make up the ArcSDE schema.

My guess is that a middle tier would be required between
PostgreSQL/PostGIS and the client to implement a versioning scheme
similar to ArcSDE.

-gary

-----Original Message-----
Subject: Re: [postgis-users] Data Versioning?


SDE is ESRIs Spatial Database Engine.  It supports versioning for
GeoSpatial data the same way that CVS does this for code.  CVS will not
work for this purpose, as Spatial Data stored in PostGIS is not stored
in flat text files like source code.  Postgres / PostGIS would need to
support this directly.

I don't have the answer to the question, but am also very interested to
know if Postgres/PostGIS support any form of geospatial data versioning.
I am also curious to know if it supports long transactions.  I should
probably RTFM before asking though.

--Craig



----- Original Message ----- 
From: "Rich Shepard" <rshepard at appl-ecosys.com>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: July 09, 2003 3:36 PM
Subject: Re: [postgis-users] Data Versioning?


> On Wed, 9 Jul 2003, Jeff McKenna wrote:
>
> > Pardon my beginner question, but I am trying to find out how 
> > PostGIS/PostgreSQL handles data versioning.  Myself I am familiar 
> > with SDE, but would love to find an open source alternative to 
> > versioning
large
> > datasets.  Does PostGIS handle data versioning?  If not, are there 
> > plans for this in the future?  Are there any documents/past email 
> > postings regarding this?  Thanks.
>
> Jeff,
>
>   I've no idea what SDE might be, but there's always CVS. This is used

> primarily for source code development projects, but I've used it for 
> document development, too. So, I imagine that one could check in and 
> out different data sets, too.
>
> Rich
>
> Dr. Richard B. Shepard, President
>
>                        Applied Ecosystem Services, Inc. (TM)