Geografic-Information-System/scripts/v.db.addtable/v.db.addtable.py

#!/usr/bin/env python
#
############################################################################
#
# MODULE:       v.db.addtable
# AUTHOR(S):    Markus Neteler
#               Converted to Python by Glynn Clements
#               Key column added by Martin Landa <landa.martin gmail.com>
#               Table index added by Markus Metz
# PURPOSE:      interface to db.execute to creates and add a new table to given vector map
# COPYRIGHT:    (C) 2005, 2007, 2008, 2011  by Markus Neteler & 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: Creates and connects a new attribute table to a given layer of an existing vector map.
#% keyword: vector
#% keyword: attribute table
#% keyword: database
#%end
#%option G_OPT_V_MAP
#%end
#%option
#% key: table
#% type: string
#% description: Name of new attribute table (default: vector map name)
#% required: no
#% guisection: Definition
#%end
#%option
#% key: layer
#% type: integer
#% description: Layer number where to add new attribute table
#% answer: 1
#% required: no
#% guisection: Definition
#%end
#%option G_OPT_DB_KEYCOLUMN
#% guisection: Definition
#%end
#%option
#% key: columns
#% type: string
#% label: Name and type of the new column(s) ('name type [,name type, ...]')
#% description: Types depend on database backend, but all support VARCHAR(), INT, DOUBLE PRECISION and DATE. Example: 'label varchar(250), value integer'
#% required: no
#% multiple: yes
#% key_desc: name type
#% guisection: Definition
#%end

import sys
import os
import grass.script as grass
from grass.script.utils import decode
from grass.exceptions import CalledModuleError


def main():
    vector = options['map']
    table = options['table']
    layer = options['layer']
    columns = options['columns']
    key = options['key']

    # does map exist in CURRENT mapset?
    mapset = grass.gisenv()['MAPSET']
    if not grass.find_file(vector, element='vector', mapset=mapset)['file']:
        grass.fatal(_("Vector map <%s> not found in current mapset") % vector)

    map_name = vector.split('@')[0]

    if not table:
        if layer == '1':
            grass.verbose(_("Using vector map name as table name: <%s>") % map_name)
            table = map_name
        else:
            # to avoid tables with identical names on higher layers
            table = "%s_%s" % (map_name, layer)
            grass.verbose(
                _("Using vector map name extended by layer number as table name: <%s>") %
                table)
    else:
        grass.verbose(_("Using user specified table name: %s") % table)

    # check if DB parameters are set, and if not set them.
    grass.run_command('db.connect', flags='c', quiet=True)
    grass.verbose(_("Creating new DB connection based on default mapset settings..."))
    kv = grass.db_connection()
    database = kv['database']
    driver = kv['driver']
    schema = kv['schema']

    database2 = database.replace('$MAP/', map_name + '/')

    # maybe there is already a table linked to the selected layer?
    nuldev = open(os.devnull, 'w')
    try:
        grass.vector_db(map_name, stderr=nuldev)[int(layer)]
        grass.fatal(_("There is already a table linked to layer <%s>") % layer)
    except KeyError:
        pass

    # maybe there is already a table with that name?
    tables = grass.read_command('db.tables', flags='p', database=database2, driver=driver,
                                stderr=nuldev)
    tables = decode(tables)

    if not table in tables.splitlines():
        colnames = []
        column_def = []
        if columns:
            column_def = []
            for x in ' '.join(columns.split()).split(','):
                colname = x.lower().split()[0]
                if colname in colnames:
                    grass.fatal(_("Duplicate column name '%s' not allowed") % colname)
                colnames.append(colname)
                column_def.append(x)

        # if not existing, create it:
        if not key in colnames:
            column_def.insert(0, "%s integer" % key)
        column_def = ','.join(column_def)

        grass.verbose(_("Creating table with columns (%s)...") % column_def)

        sql = "CREATE TABLE %s (%s)" % (table, column_def)
        try:
            grass.run_command('db.execute',
                              database=database2, driver=driver, sql=sql)
        except CalledModuleError:
            grass.fatal(_("Unable to create table <%s>") % table)

    # connect the map to the DB:
    if schema:
        table = '{schema}.{table}'.format(schema=schema, table=table)
    grass.verbose(_("Connecting new table to vector map <%s>...") % map_name)
    grass.run_command('v.db.connect', quiet=True,
                      map=map_name, database=database, driver=driver,
                      layer=layer, table=table, key=key)

    # finally we have to add cats into the attribute DB to make
    # modules such as v.what.rast happy: (creates new row for each
    # vector line):
    try:
        grass.run_command('v.to.db', map=map_name, layer=layer,
                          option='cat', column=key, qlayer=layer)
    except CalledModuleError:
        # remove link
        grass.run_command('v.db.connect', quiet=True, flags='d',
                          map=map_name, layer=layer)
        return 1

    grass.verbose(_("Current attribute table links:"))
    if grass.verbosity() > 2:
        grass.run_command('v.db.connect', flags='p', map=map_name)

    # write cmd history:
    grass.vector_history(map_name)

    return 0

if __name__ == "__main__":
    options, flags = grass.parser()
    sys.exit(main())