This RnD page is set up to explore the pandora's box opened by the postgis-versioned module; and see it it can be cleaned up as a more general purpose solution suitable for use by geogit, arcsde, oracle and postgis-versioned.

Table of contents:

Children:

Reference:

Scope

This work is being undertaken by LISAsoft to define a datastore used to store and access revisions. We have not chosen a backend at this time - the following are under consideration:

Also for consideration:

Timeline:

*Version Model*

The use of the word "version" changes between different back-ends - as such I will try and use the following in a consistent manner:

PostGIS-Versioned

The module would need work to migrate to JDBC-NG (and discussion with Justin as JDBC-NG classes are all marked final.

The details on migration to JDBC-NG are slightly off topic (although interesting) - as such a couple of options are listed below:

Option: Extend JDBCDataStore

Option: Modify JDBCDataStore - boil the concept of versioning into the JDBCDataStore; an ability that would not be leveraged by the default implementations. For this to work:

Option: "Pure" DataStoreWrapper

*Version Model*

This datastore captures:

GeoGIT

The GeoGIT project is GPL; in part to make use of Binary XMl from the gvSig project.

Option: Ignore the project as not compatible with GeoTools / LGPL

Option: Ask for the project to be LGPL; and rewrite the binary XML part. Conversation with Gabriel indicates this is around two months to do

Option: Ask for GeoGIT to to be LGPL: and ask gvSIG to release the binary XML part under some license we can use

We understand this project is only taking shape now; and follows a model where a dataset can be "unpacked" into a normal DataStore. Even with this model we would still need the ability to query revision history as per the VersioningDataStore API defined by postgis-versioning.

*Version Model*

WFS 2

Justin is implementing WFS 2.0; as such there is a couple things we need to keep in mind.

*Query*

Q: Supports the concept of Version; not sure if that is the ArcSDE model (ie a branch of the dataset); or trying to indicate a revision of a feature.

Q: Not sure how to query revision history (ie single feature; get the historical changes)

ArcSDE

TBD

*Version Model*

Oracle

Oracle supports "long term transaction support"; a model similar to the ArcSDE concept of "versions". Update: They renamed the functionality as "workspace manager".

*Version Model*

For "versioned enabled tables":

*Reference*

Prior work from postgis-versioned module: