[GRASS5] Questions about v.to.db and table update from v.digit

I’ve run into a couple of items that I hope someone can clarify.

1st v.to.db: What does query mode do and how does it work? There is no explanation for this in docs. I’ve tried various trial and error (clearly all error so far) and I can’t get anything to give any results using query mode. Also, there is a suggestion that you can list multiple columns for the col argument, but this produces an error. Is this not implemented yet or is my syntax wrong (column,column,…)

2nd table update in v.digit: Sometimes it works and sometimes it doesn’t. I made a table to go along with the Spearfish streams vector file (after giving unique cat values to each stream segment). I can query it and update values with v.to.db. I tried to change a value in v.digit and I consistently received the following error when I try to replace 0 with 2 in the order column.

Cannot update table:
DBMI-DBF driver error:
SQL parser error in statement:
update streams set ORDER = 2, LENGTH = 3488.474000 where cat = 21
Error in db_execute_immediate()

Thanks for any clarification.

Michael


C. Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
PO Box 872402
Arizona State University
Tempe, AZ 85287-2402
USA

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>