[GRASS-user] link one to many-sqlite

[Moritz Lennert]

On 27/03/09 00:13, Gabriele N. wrote:
> Hi. I'm working with  grass64 on ubuntu 8.10. I have created a sqlite
> db. 1) I have a shape of municipalities that have problems of
> topology. In addition, some municipalities have more non-adjacent
> areas. To not have the municipalities 'split' I tried to import
> without topological corrections but I do not think is the right
> thing. v.dissolve does not work if the polygons are not adjacent.
> Right?

What are you trying to achieve exactly ? Fusion non-adjacent polygons or
give them all the same category value ? If the later, then you can use
v.reclass on the column containing the common code (as long as this is
an integer).

> 
> 2) In addition to the linked table, I want to connect another table
> but it has many records for each municipalities and then to do a link
> one to many (see picture example in attachment).

There was no attachment... Do I understand correctly that for one 
category value you will have several tuples in a table giving different 
information concerning this same category ? That's seems like a definite 
"don't do" to me.

> link_table.gif 
> Should I put this table on layer 2? or create a copy of the shape and
> try to connect this table? 

Or (although not sure if I understand exactly what your objectif is): 
create a view in sqlite combining the currently attached and the other 
table and then v.db.connect your map to that view.

> I have attached the table with
> v.db.connect on layer 2 and it seems ok, but if I query the poligon
> (identify in display mode) opens the table only on layer 1.

Do your features have category values in layer 2 ? If not, you can
attach as many tables as you want, but there will be no features that
correspond to the tuples in these tables.

Moritz