[GRASS-dev] Major changes in the temporal framework

Sören Gebbert soerengebbert at googlemail.com
Mon Dec 30 18:23:22 PST 2013

Dear all,
just for your information:

I will commit several modification to the temporal framework (grass7
trunk) in a few minutes. :)

The modifications are not backward compatible, hence existing temporal
databases, independently from the used backend (sqlite or postgresql)
WILL NOT WORK with the new framework.

The modifications:
- Removed the creation of a register table for each registered map,
which speeds things up massively
- Added modification time to space time datasets
- Added aggregation type to space time datasets that will be set by
- Keeping the SQL scripts as simple as possible
- Removed foreign primary keys and created indexes for primary keys in
sqlite3 (postgreql does this automagically)
- Using delete trigger instead of foreign primary keys in postgresql backend
- Removed unneeded SQL scripts
- Using Python dateutil module for time string parsing if installed,
or a much more simpler parser without time zone support
- Added GRASS environmental variables to allow registration of maps
from different mapsets in a space time dataset
- Simplified code for map registration
- Code cleanup ...

Best regards

2013/12/22 Sören Gebbert <soerengebbert at googlemail.com>:
> Dear all,
> just for your information:
> I will commit several modification to the temporal framework (grass7
> trunk) in the next weeks, that will change the SQL database layout and
> the API. The goal is to make the temporal frameworks SQL database
> interaction much faster, reducing the number of tables to scale better
> with tens of thousand of maps, improving the PostgreSQL
> compatibility/performance and make it better maintainable.
> The changes will result in backward incompatibility. Hence, the new
> framework will not work with existing temporal databases. The changes
> are too drastic to provide backward compatibility. I will introduce
> new tables and columns and completely remove the creation of tables
> for each registered map. I will remove several functions from the API
> and introduce new classes and functions. To get an idea of the changes
> have a look at [2].
> Please use the export tools (t.rast.export and t.vect.export) to
> transfer your temporal data into the new temporal database, or simply
> use t.*.list[1] tools to create text files that can be used for
> re-registering of raster, vector and voxel maps in the new temporal
> framework.
> I will inform you before the first commit that will introduce the
> incompatibility.
> Best regards
> Soeren
> [1] "t.rast.list input=my_strds columns=name,start_time,end_time > map_list.txt"
> [2] http://pastebin.de/38117

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