[STATSGRASS] Tables in PostgreSQL

[Pelfer PG&G]

Hello,

I am using GRASS and PostgreSQL for an Archaeological GIS about spatial 
analysis and settlement pattern evolution in a case study of the South 
Etruria.
I am writing the tables of the alphanumeric and textual data on PostgreSQL, 
it works well but I had these problems:

1)- I can not cancel the single columns from an existing table.

I tried with

ALTER TABLE tablename DROP COLUMN columnname datatype (es. int2);

But it indicated me syntax errors in string writing.

2)- How it is possible to change in the tables the existing data types (es 
from text to smallint) of the single columns?


Thanks in advance for your help


Giuliano Pelfer
Ph Student in Ancient Topography and Landscape Archaeology
University of Bologna/Roma