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#!/usr/bin/env python3
#
############################################################################
#
# MODULE: v.db.update
# AUTHOR(S): Moritz Lennert
# Extensions by Markus Neteler
# Converted to Python by Glynn Clements
# PURPOSE: Interface to db.execute to update a column in the attribute table connected to a given map
# COPYRIGHT: (C) 2005-2014 by the GRASS Development Team
#
# This program is free software under the GNU General Public
# License (>=v2). Read the file COPYING that comes with GRASS
# for details.
#
#############################################################################
# %module
# % description: Updates a column in the attribute table connected to a vector map.
# % keyword: vector
# % keyword: attribute table
# % keyword: database
# % keyword: attribute update
# % keyword: type casting
# %end
# %option G_OPT_V_MAP
# %end
# %option G_OPT_V_FIELD
# % required: yes
# %end
# %option G_OPT_DB_COLUMN
# % key: column
# % description: Name of attribute column to update
# % required: yes
# %end
# %option
# % key: value
# % type: string
# % description: Literal value to update the column with
# % required: no
# %end
# %option G_OPT_DB_COLUMN
# % key: query_column
# % description: Name of other attribute column to query, can be combination of columns (e.g. co1+col2)
# %end
# %option G_OPT_DB_WHERE
# %end
# %option G_OPT_F_INPUT
# % key: sqliteextra
# % description: Name of SQLite extension file for extra functions (SQLite backend only)
# % gisprompt: old,bin,file
# % required: no
# %end
import sys
import os
import grass.script as grass
def main():
vector = options["map"]
layer = options["layer"]
column = options["column"]
value = options["value"]
qcolumn = options["query_column"]
where = options["where"]
sqlitefile = options["sqliteextra"]
mapset = grass.gisenv()["MAPSET"]
# does map exist in CURRENT mapset?
if not grass.find_file(vector, element="vector", mapset=mapset)["file"]:
grass.fatal(_("Vector map <%s> not found in current mapset") % vector)
try:
f = grass.vector_db(vector)[int(layer)]
except KeyError:
grass.fatal(
_(
"There is no table connected to this map. Run v.db.connect or v.db.addtable first."
)
)
table = f["table"]
database = f["database"]
driver = f["driver"]
# check for SQLite backend for extra functions
if sqlitefile and driver != "sqlite":
grass.fatal(_("Use of libsqlitefunctions only with SQLite backend"))
if driver == "sqlite" and sqlitefile:
if not os.access(sqlitefile, os.R_OK):
grass.fatal(_("File <%s> not found") % sqlitefile)
# Check column existence and get its type.
all_columns = grass.vector_columns(vector, layer)
coltype = None
for column_name, column_record in all_columns.items():
if column.lower() == column_name.lower():
coltype = column_record["type"]
break
if not coltype:
grass.fatal(_("Column <%s> not found") % column)
if qcolumn:
if value:
grass.fatal(_("<value> and <qcolumn> are mutually exclusive"))
# special case: we copy from another column
value = qcolumn
else:
if not value:
grass.fatal(_("Either <value> or <qcolumn> must be given"))
# we insert a value
if coltype.upper() not in ["INTEGER", "DOUBLE PRECISION"]:
value = "'%s'" % value
cmd = "UPDATE %s SET %s=%s" % (table, column, value)
if where:
cmd += " WHERE " + where
# SQLite: preload extra functions from extension lib if provided by user
if sqlitefile:
sqliteload = "SELECT load_extension('%s');\n" % sqlitefile
cmd = sqliteload + cmd
grass.verbose('SQL: "%s"' % cmd)
grass.write_command(
"db.execute", input="-", database=database, driver=driver, stdin=cmd
)
# write cmd history:
grass.vector_history(vector)
return 0
if __name__ == "__main__":
options, flags = grass.parser()
sys.exit(main())
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