[GRASS-user] v.db.connect, categories, and postgresql database queries

[William Hudspeth]

Hello all,

I am trying to make a connection between a GRASS vector map and an
attribute table stored in Postgresql. I can see and query the attribute
table with db.connect and db.select, but I cannot seem to do so with
v.db.connect or v.db.select. It seems that the problem perhaps has
something to do with the fact that the postgres attribute table is
lacking a cat field, but I don't understand how the field is created and
used in subsequent query operations. Could someone please provide an
explanation and series of directions on how I link vector maps to
attribute tables, and how the cat fields are involved. The online
documentation is not particularly clear in this area. I would like
ultimately to display (d.vect) vector map records based on values found
in the postgres attribute table.

Thanks for any help.

Bill