nominatim/tools/refresh.py

   1 """
   2 Functions for bringing auxiliary data in the database up-to-date.
   3 """
   4 import json
   5
   6 from psycopg2.extras import execute_values
   7
   8 from ..db.utils import execute_file
   9
  10 def update_postcodes(conn, datadir):
  11     """ Recalculate postcode centroids and add, remove and update entries in the
  12         location_postcode table. `conn` is an opne connection to the database.
  13     """
  14     execute_file(conn, datadir / 'sql' / 'update-postcodes.sql')
  15
  16
  17 def recompute_word_counts(conn, datadir):
  18     """ Compute the frequency of full-word search terms.
  19     """
  20     execute_file(conn, datadir / 'sql' / 'words_from_search_name.sql')
  21
  22
  23 def _add_address_level_rows_from_entry(rows, entry):
  24     """ Converts a single entry from the JSON format for address rank
  25         descriptions into a flat format suitable for inserting into a
  26         PostgreSQL table and adds these lines to `rows`.
  27     """
  28     countries = entry.get('countries') or (None, )
  29     for key, values in entry['tags'].items():
  30         for value, ranks in values.items():
  31             if isinstance(ranks, list):
  32                 rank_search, rank_address = ranks
  33             else:
  34                 rank_search = rank_address = ranks
  35             if not value:
  36                 value = None
  37             for country in countries:
  38                 rows.append((country, key, value, rank_search, rank_address))
  39
  40 def load_address_levels(conn, table, levels):
  41     """ Replace the `address_levels` table with the contents of `levels'.
  42
  43         A new table is created any previously existing table is dropped.
  44         The table has the following columns:
  45             country, class, type, rank_search, rank_address
  46     """
  47     rows = []
  48     for entry in levels:
  49         _add_address_level_rows_from_entry(rows, entry)
  50
  51     with conn.cursor() as cur:
  52         cur.execute('DROP TABLE IF EXISTS {}'.format(table))
  53
  54         cur.execute("""CREATE TABLE {} (country_code varchar(2),
  55                                         class TEXT,
  56                                         type TEXT,
  57                                         rank_search SMALLINT,
  58                                         rank_address SMALLINT)""".format(table))
  59
  60         execute_values(cur, "INSERT INTO {} VALUES %s".format(table), rows)
  61
  62         cur.execute('CREATE UNIQUE INDEX ON {} (country_code, class, type)'.format(table))
  63
  64     conn.commit()
  65
  66 def load_address_levels_from_file(conn, config_file):
  67     """ Replace the `address_levels` table with the contents of the config
  68         file.
  69     """
  70     with config_file.open('r') as fdesc:
  71         load_address_levels(conn, 'address_levels', json.load(fdesc))