Hi Juan, the following link should be interesting:
http://pgfoundry.org/projects/tablelog/ tablelog adresses your problem and tracks the historical state of your table (including geometry). "PostgreSQL Table Log uses a trigger to log any INSERTs, UPDATEs and DELETEs on a specific table into another table. The second part of tablelog is able to restore the state of the original table or of a specific row for any time in the past." greetings, Johannes -------- Original-Nachricht -------- > Datum: Wed, 13 May 2009 14:43:06 -0700 > Von: Paul Ramsey <[email protected]> > An: [email protected], PostGIS Users Discussion > <[email protected]> > Betreff: Re: [postgis-users] Versioning > Then you should be able to get by with a pretty simple system. > For each table you want to retain history for, add a second table, > table_history that adds two columns (date_added, date_deleted). > The put some insert/update/delete triggers on your main tables. > - on insert of row, simultaneously insert a copy into the _history > table with an appropriate date_added > - on delete of row update the date_deleted field in the equivalent > _history table row > - on update of row, flag the current copy of the row as deleted, and > add a new copy of the row with the current date as the added date > > Now a snapshot of "historical state" as of date_query is as simple as > querying the history table for "date_added < date_query and > (date_deleted > date_query or date_deleted is null)" > > The thrifty among us will say "hey, I can just have one table with > date_added and date_deleted columns" and "current state is just all > records with "date_deleted is null". However, your table will grow > over time, and eventually things will get slower than you would like. > Having a "working table" that is just current also removes the need > for client applications to understand the "history concept", they can > just work on the table as normal and history is maintained for them > transparently. > > P. > > > 2009/5/13 Juan Pedro Pérez Alcántara <[email protected]>: > > Sure, you right. I'm refering versioning in it's first meaning, that is, > > history tracking. > > > > Thanks, > > > > Juan Pedro Pérez Alcántara > > > > On Wed, 2009-05-13 at 12:33 -0700, Paul Ramsey wrote: > >> Juan Pedro, > >> > >> What do you mean by "versioning"? > >> > >> History tracking? (Every state of the data is one version, but there > >> is only one branch of the data.) > >> Branching and merging? (People can take a copy of the data (a version) > >> and work on it, then merge it back into the main database.) > >> > >> Versioning is an overloaded word. Describe your actual use case. > >> > >> P. > >> > >> 2009/5/13 Juan Pedro Pérez Alcántara <[email protected]>: > >> > Hello all, > >> > > >> > soon we will face a project which will need a really strong > > versioning > >> > mechanism, including geometry. I'm sure anybody here have already > >> > addressed this sort of problem. I wonder if you can drop a line or > > two > >> > about this issue, for I consider it hard to implement. Sure the > >> > solutions will vary wildly depending on the scenario, the data, the > >> > versioning schedule, etc., but I'll be glad to hear about your > >> > experiences in that field. > >> > > >> > Greetings, > >> > > >> > Juan Pedro Pérez Alcántara > >> > > >> > > >> > _______________________________________________ > >> > postgis-users mailing list > >> > [email protected] > >> > http://postgis.refractions.net/mailman/listinfo/postgis-users > >> > > >> > > > > > > _______________________________________________ > > postgis-users mailing list > > [email protected] > > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users -- Neu: GMX FreeDSL Komplettanschluss mit DSL 6.000 Flatrate + Telefonanschluss für nur 17,95 Euro/mtl.!* http://dslspecial.gmx.de/freedsl-surfflat/?ac=OM.AD.PD003K11308T4569a _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
