[GRASS-user] Tutorial & help needed::join tables (which are stored in postgres) and export result

[wqual]

Dear list,
I am still testing, what kind of database I should use for my work with 
GRASS/QGIS. As my experiences with sqlite3 where not that positive (large 
datasets took very much time to be read into sqlite), I started working with 
postgres (and my first impression is that it's far more faster). dbf is 
quick, but does not offer me the possibility to perform "table-join", which I 
need every day. 
I am not that experienced with pg, therefore, I would like to ask you folks 
some questions about "daily GIS work with postgres in GRASS":

* How can I join pg-tables in GRASS, can I export a joined theme to make it 
permanent (for example, I would like to create a shapefile out of it which 
contains all information of the join)

* Does anybody has experience with pg-frontends like knoda and pg_admin? 
Working with tables on the command-line is hard for people who used *other 
programmes* before ;)

* what about large datasets: shapefiles with *qix-files seem to be loaded 
faster compared the same theme in GRASS with its attributes in postgres

* tutorials available for this pg-stuff inside of GRASS?

Any comments / hints are greatly appreciated!

Best regards,
Wolfgang