[GRASSLIST:4368] Re: Grass57 Vector attributes

Radim Blazek blazek at itc.it
Fri Sep 17 11:10:30 EDT 2004


On Wednesday 15 September 2004 13:36, Michael Holzmann wrote:
>  -with v.external now I make  a Postgis-DB connection with the Layer
> state1. The geometry data are o.k. but the attributes doesn`t appear. The
> result of a query 	results in :
> Cannot open select cursor:`select*from
> state1 where FID=69` on database`PG:localhost....,

Yes, bug and difficult to resolve I think. OGR layers use FID 
as link to attributes. OGR SQL doc says:
(http://gdal.maptools.org/ogr/ogr_sql.html)

| FID
| 
| Normally the feature id is a special property of a feature and not treated 
| as an attribute of the feature. In some cases it is convenient to be able 
| to utilize the feature id in queries and result sets as a regular field. 
| To do so use the name FID. The field wildcard expansions will not include 
| the feature id, but it may be explicitly included using a syntax like:
| 
| SELECT FID, * FROM nation

But for Postgres and other RDBMS, the query is probably passed 
to the server, so the query fails, because FID field does not exist.

Frank, 
how to get FID column name (pszFIDColumn, I believe)?

Radim




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