rework postcode computation

Now adds areas to location_postcodes, ignores postcode points
inside areas and supports customizable extents.

lib-sql/functions/postcode_triggers.sql

@@ -2,10 +2,10 @@
 --
 -- This file is part of Nominatim. (https://nominatim.org)
 --
--- Copyright (C) 2022 by the Nominatim developer community.
+-- Copyright (C) 2025 by the Nominatim developer community.
 -- For a full list of authors see the git log.
 
--- Trigger functions for location_postcode table.
+-- Trigger functions for location_postcodes table.
 
 
 -- Trigger for updates of location_postcode
@@ -13,7 +13,7 @@
 -- Computes the parent object the postcode most likely refers to.
 -- This will be the place that determines the address displayed when
 -- searching for this postcode.
-CREATE OR REPLACE FUNCTION postcode_update()
+CREATE OR REPLACE FUNCTION postcodes_update()
   RETURNS TRIGGER
   AS $$
 DECLARE
@@ -28,13 +28,10 @@ BEGIN
 
     partition := get_partition(NEW.country_code);
 
-    SELECT * FROM get_postcode_rank(NEW.country_code, NEW.postcode)
-      INTO NEW.rank_search, NEW.rank_address;
-
     NEW.parent_place_id = 0;
     FOR location IN
       SELECT place_id
-        FROM getNearFeatures(partition, NEW.geometry, NEW.geometry, NEW.rank_search)
+        FROM getNearFeatures(partition, NEW.centroid, NEW.centroid, NEW.rank_search)
         WHERE NOT isguess ORDER BY rank_address DESC, distance asc LIMIT 1
     LOOP
         NEW.parent_place_id = location.place_id;
@@ -45,3 +42,89 @@ END;
 $$
 LANGUAGE plpgsql;
 
+
+CREATE OR REPLACE FUNCTION postcodes_delete()
+  RETURNS TRIGGER
+  AS $$
+BEGIN
+{% if not disable_diff_updates %}
+  UPDATE placex p SET indexed_status = 2
+   WHERE p.postcode = OLD.postcode AND ST_Intersects(OLD.geometry, p.geometry)
+         AND indexed_status = 0;
+{% endif %}
+
+  RETURN OLD;
+END;
+$$
+LANGUAGE plpgsql;
+
+
+CREATE OR REPLACE FUNCTION postcodes_insert()
+  RETURNS TRIGGER
+  AS $$
+DECLARE
+  existing RECORD;
+BEGIN
+  IF NEW.osm_id is not NULL THEN
+    -- postcode area, remove existing from same OSM object
+    SELECT * INTO existing FROM location_postcodes p
+      WHERE p.osm_id = NEW.osm_id;
+
+    IF existing.place_id is not NULL THEN
+      IF existing.postcode != NEW.postcode or existing.country_code != NEW.country_code THEN
+        DELETE FROM location_postcodes p WHERE p.osm_id = NEW.osm_id;
+        existing := NULL;
+      END IF;
+    END IF;
+  END IF;
+
+  IF existing is NULL THEN
+    SELECT * INTO existing FROM location_postcodes p
+      WHERE p.country_code = NEW.country_code AND p.postcode = NEW.postcode;
+
+    IF existing.postcode is NULL THEN
+{% if not disable_diff_updates %}
+      UPDATE placex p SET indexed_status = 2
+       WHERE ST_Intersects(NEW.geometry, p.geometry)
+             AND indexed_status = 0
+             AND p.rank_address >= 22 AND not p.address ? 'postcode';
+{% endif %}
+
+      -- new entry, just insert
+      NEW.indexed_status := 1;
+      NEW.place_id := nextval('seq_place');
+      RETURN NEW;
+    END IF;
+  END IF;
+
+  -- update: only when there are changes
+  IF coalesce(NEW.osm_id, -1) != coalesce(existing.osm_id, -1)
+     OR (NEW.osm_id is not null AND NEW.geometry::text != existing.geometry::text)
+     OR (NEW.osm_id is null
+         AND (abs(ST_X(existing.centroid) - ST_X(NEW.centroid)) > 0.0000001
+              OR abs(ST_Y(existing.centroid) - ST_Y(NEW.centroid)) > 0.0000001))
+  THEN
+{% if not disable_diff_updates %}
+    UPDATE placex p SET indexed_status = 2
+      WHERE ST_Intersects(ST_Difference(NEW.geometry, existing.geometry), p.geometry)
+            AND indexed_status = 0
+            AND p.rank_address >= 22 AND not p.address ? 'postcode';
+
+    UPDATE placex p SET indexed_status = 2
+      WHERE ST_Intersects(ST_Difference(existing.geometry, NEW.geometry), p.geometry)
+            AND indexed_status = 0
+            AND p.postcode = OLD.postcode;
+{% endif %}
+
+    UPDATE location_postcodes p
+      SET osm_id = NEW.osm_id,
+          indexed_status = 2,
+          centroid = NEW.centroid,
+          geometry = NEW.geometry
+      WHERE p.country_code = NEW.country_code AND p.postcode = NEW.postcode;
+  END IF;
+
+  RETURN NULL;
+END;
+$$
+LANGUAGE plpgsql;

lib-sql/functions/ranking.sql

@@ -2,7 +2,7 @@
 --
 -- This file is part of Nominatim. (https://nominatim.org)
 --
--- Copyright (C) 2022 by the Nominatim developer community.
+-- Copyright (C) 2025 by the Nominatim developer community.
 -- For a full list of authors see the git log.
 
 -- Functions related to search and address ranks
@@ -114,66 +114,6 @@ $$
 LANGUAGE plpgsql IMMUTABLE PARALLEL SAFE;
 
 
--- Guess a ranking for postcodes from country and postcode format.
-CREATE OR REPLACE FUNCTION get_postcode_rank(country_code VARCHAR(2), postcode TEXT,
-                                             OUT rank_search SMALLINT,
-                                             OUT rank_address SMALLINT)
-AS $$
-DECLARE
-  part TEXT;
-BEGIN
-    rank_search := 30;
-    rank_address := 30;
-    postcode := upper(postcode);
-
-    IF country_code = 'gb' THEN
-        IF postcode ~ '^([A-Z][A-Z]?[0-9][0-9A-Z]? [0-9][A-Z][A-Z])$' THEN
-            rank_search := 25;
-            rank_address := 5;
-        ELSEIF postcode ~ '^([A-Z][A-Z]?[0-9][0-9A-Z]? [0-9])$' THEN
-            rank_search := 23;
-            rank_address := 5;
-        ELSEIF postcode ~ '^([A-Z][A-Z]?[0-9][0-9A-Z])$' THEN
-            rank_search := 21;
-            rank_address := 5;
-        END IF;
-
-    ELSEIF country_code = 'sg' THEN
-        IF postcode ~ '^([0-9]{6})$' THEN
-            rank_search := 25;
-            rank_address := 11;
-        END IF;
-
-    ELSEIF country_code = 'de' THEN
-        IF postcode ~ '^([0-9]{5})$' THEN
-            rank_search := 21;
-            rank_address := 11;
-        END IF;
-
-    ELSE
-        -- Guess at the postcode format and coverage (!)
-        IF postcode ~ '^[A-Z0-9]{1,5}$' THEN -- Probably too short to be very local
-            rank_search := 21;
-            rank_address := 11;
-        ELSE
-            -- Does it look splitable into and area and local code?
-            part := substring(postcode from '^([- :A-Z0-9]+)([- :][A-Z0-9]+)$');
-
-            IF part IS NOT NULL THEN
-                rank_search := 25;
-                rank_address := 11;
-            ELSEIF postcode ~ '^[- :A-Z0-9]{6,}$' THEN
-                rank_search := 21;
-                rank_address := 11;
-            END IF;
-        END IF;
-    END IF;
-
-END;
-$$
-LANGUAGE plpgsql IMMUTABLE PARALLEL SAFE;
-
-
 -- Get standard search and address rank for an object.
 --
 -- \param country        Two-letter country code where the object is in.
@@ -198,12 +138,7 @@ AS $$
 DECLARE
   classtype TEXT;
 BEGIN
-  IF place_class in ('place','boundary')
-     and place_type in ('postcode','postal_code')
-  THEN
-    SELECT * INTO search_rank, address_rank
-      FROM get_postcode_rank(country, postcode);
-  ELSEIF extended_type = 'N' AND place_class = 'highway' THEN
+  IF extended_type = 'N' AND place_class = 'highway' THEN
     search_rank = 30;
     address_rank = 30;
   ELSEIF place_class = 'landuse' AND extended_type != 'A' THEN

lib-sql/functions/utils.sql

@@ -323,6 +323,17 @@ END;
 $$
 LANGUAGE plpgsql;
 
+
+-- Return the bounding box of the geometry buffered by the given number
+-- of meters.
+CREATE OR REPLACE FUNCTION expand_by_meters(geom GEOMETRY, meters FLOAT)
+  RETURNS GEOMETRY
+  AS $$
+    SELECT ST_Envelope(ST_Buffer(geom::geography, meters, 1)::geometry)
+$$
+LANGUAGE sql IMMUTABLE PARALLEL SAFE;
+
+
 -- Create a bounding box with an extent computed from the radius (in meters)
 -- which in turn is derived from the given search rank.
 CREATE OR REPLACE FUNCTION place_node_fuzzy_area(geom GEOMETRY, rank_search INTEGER)
@@ -341,9 +352,7 @@ BEGIN
     radius := 1000;
   END IF;
 
-  RETURN ST_Envelope(ST_Collect(
-                     ST_Project(geom::geography, radius, 0.785398)::geometry,
-                     ST_Project(geom::geography, radius, 3.9269908)::geometry));
+  RETURN expand_by_meters(geom, radius);
 END;
 $$
 LANGUAGE plpgsql IMMUTABLE PARALLEL SAFE;

lib-sql/table-triggers.sql

@@ -26,4 +26,8 @@ CREATE TRIGGER place_before_insert BEFORE INSERT ON place
     FOR EACH ROW EXECUTE PROCEDURE place_insert();
 
 CREATE TRIGGER location_postcode_before_update BEFORE UPDATE ON location_postcodes
-    FOR EACH ROW EXECUTE PROCEDURE postcode_update();
+    FOR EACH ROW EXECUTE PROCEDURE postcodes_update();
+CREATE TRIGGER location_postcodes_before_delete BEFORE DELETE ON location_postcodes
+    FOR EACH ROW EXECUTE PROCEDURE postcodes_delete();
+CREATE TRIGGER location_postcodes_before_insert BEFORE INSERT ON location_postcodes
+    FOR EACH ROW EXECUTE PROCEDURE postcodes_insert();

src/nominatim_db/tools/postcodes.py

@@ -8,7 +8,7 @@
 Functions for importing, updating and otherwise maintaining the table
 of artificial postcode centroids.
 """
-from typing import Optional, Tuple, Dict, List, TextIO
+from typing import Optional, Tuple, Dict, TextIO
 from collections import defaultdict
 from pathlib import Path
 import csv
@@ -38,13 +38,26 @@ def _to_float(numstr: str, max_value: float) -> float:
     return num
 
 
+def _extent_to_rank(extent: int) -> int:
+    """ Guess a suitable search rank from the extent of a postcode.
+    """
+    if extent <= 100:
+        return 25
+    if extent <= 3000:
+        return 23
+    return 21
+
+
 class _PostcodeCollector:
     """ Collector for postcodes of a single country.
     """
 
-    def __init__(self, country: str, matcher: Optional[CountryPostcodeMatcher]):
+    def __init__(self, country: str, matcher: Optional[CountryPostcodeMatcher],
+                 default_extent: int, exclude: set[str] = set()):
         self.country = country
         self.matcher = matcher
+        self.extent = default_extent
+        self.exclude = exclude
         self.collected: Dict[str, PointsCentroid] = defaultdict(PointsCentroid)
         self.normalization_cache: Optional[Tuple[str, Optional[str]]] = None
 
@@ -61,7 +74,7 @@ class _PostcodeCollector:
                 normalized = self.matcher.normalize(match) if match else None
                 self.normalization_cache = (postcode, normalized)
 
-            if normalized:
+            if normalized and normalized not in self.exclude:
                 self.collected[normalized] += (x, y)
 
     def commit(self, conn: Connection, analyzer: AbstractAnalyzer,
@@ -73,61 +86,37 @@ class _PostcodeCollector:
         """
         if project_dir is not None:
             self._update_from_external(analyzer, project_dir)
-        to_add, to_delete, to_update = self._compute_changes(conn)
 
-        LOG.info("Processing country '%s' (%s added, %s deleted, %s updated).",
-                 self.country, len(to_add), len(to_delete), len(to_update))
+        with conn.cursor() as cur:
+            cur.execute("""SELECT postcode FROM location_postcodes
+                           WHERE country_code = %s AND osm_id is null""",
+                        (self.country, ))
+            to_delete = [row[0] for row in cur if row[0] not in self.collected]
+
+        to_add = [dict(zip(('pc', 'x', 'y'), (k, *v.centroid())))
+                  for k, v in self.collected.items()]
+        self.collected = defaultdict(PointsCentroid)
+
+        LOG.info("Processing country '%s' (%s added, %s deleted).",
+                 self.country, len(to_add), len(to_delete))
 
         with conn.cursor() as cur:
             if to_add:
                 cur.executemany(pysql.SQL(
-                    """INSERT INTO location_postcode
-                         (place_id, indexed_status, country_code,
-                          postcode, geometry)
-                       VALUES (nextval('seq_place'), 1, {}, %s,
-                               ST_SetSRID(ST_MakePoint(%s, %s), 4326))
-                    """).format(pysql.Literal(self.country)),
+                    """INSERT INTO location_postcodes
+                         (country_code, rank_search, postcode, centroid, geometry)
+                       VALUES ({}, {}, %(pc)s,
+                               ST_SetSRID(ST_MakePoint(%(x)s, %(y)s), 4326),
+                               expand_by_meters(ST_SetSRID(ST_MakePoint(%(x)s, %(y)s), 4326), {}))
+                    """).format(pysql.Literal(self.country),
+                                pysql.Literal(_extent_to_rank(self.extent)),
+                                pysql.Literal(self.extent)),
                     to_add)
             if to_delete:
-                cur.execute("""DELETE FROM location_postcode
+                cur.execute("""DELETE FROM location_postcodes
                                WHERE country_code = %s and postcode = any(%s)
+                                     AND osm_id is null
                             """, (self.country, to_delete))
-            if to_update:
-                cur.executemany(
-                    pysql.SQL("""UPDATE location_postcode
-                                 SET indexed_status = 2,
-                                     geometry = ST_SetSRID(ST_Point(%s, %s), 4326)
-                                 WHERE country_code = {} and postcode = %s
-                              """).format(pysql.Literal(self.country)),
-                    to_update)
-
-    def _compute_changes(
-            self, conn: Connection
-            ) -> Tuple[List[Tuple[str, float, float]], List[str], List[Tuple[float, float, str]]]:
-        """ Compute which postcodes from the collected postcodes have to be
-            added or modified and which from the location_postcode table
-            have to be deleted.
-        """
-        to_update = []
-        to_delete = []
-        with conn.cursor() as cur:
-            cur.execute("""SELECT postcode, ST_X(geometry), ST_Y(geometry)
-                           FROM location_postcode
-                           WHERE country_code = %s""",
-                        (self.country, ))
-            for postcode, x, y in cur:
-                pcobj = self.collected.pop(postcode, None)
-                if pcobj:
-                    newx, newy = pcobj.centroid()
-                    if abs(x - newx) > 0.0000001 or abs(y - newy) > 0.0000001:
-                        to_update.append((newx, newy, postcode))
-                else:
-                    to_delete.append(postcode)
-
-        to_add = [(k, *v.centroid()) for k, v in self.collected.items()]
-        self.collected = defaultdict(PointsCentroid)
-
-        return to_add, to_delete, to_update
 
     def _update_from_external(self, analyzer: AbstractAnalyzer, project_dir: Path) -> None:
         """ Look for an external postcode file for the active country in
@@ -152,7 +141,7 @@ class _PostcodeCollector:
                                     _to_float(row['lat'], 90))
                         self.collected[postcode] += centroid
                     except ValueError:
-                        LOG.warning("Bad coordinates %s, %s in %s country postcode file.",
+                        LOG.warning("Bad coordinates %s, %s in '%s' country postcode file.",
                                     row['lat'], row['lon'], self.country)
 
         finally:
@@ -175,63 +164,158 @@ class _PostcodeCollector:
 
 
 def update_postcodes(dsn: str, project_dir: Optional[Path], tokenizer: AbstractTokenizer) -> None:
-    """ Update the table of artificial postcodes.
-
-        Computes artificial postcode centroids from the placex table,
-        potentially enhances it with external data and then updates the
-        postcodes in the table 'location_postcode'.
+    """ Update the table of postcodes from the input tables
+        placex and place_postcode.
     """
     matcher = PostcodeFormatter()
     with tokenizer.name_analyzer() as analyzer:
         with connect(dsn) as conn:
-            # First get the list of countries that currently have postcodes.
-            # (Doing this before starting to insert, so it is fast on import.)
-            with conn.cursor() as cur:
-                cur.execute("SELECT DISTINCT country_code FROM location_postcode")
-                todo_countries = set((row[0] for row in cur))
-
-            # Recompute the list of valid postcodes from placex.
-            with conn.cursor(name="placex_postcodes") as cur:
-                cur.execute("""
-                SELECT cc, pc, ST_X(centroid), ST_Y(centroid)
-                FROM (SELECT
-                        COALESCE(plx.country_code,
-                                 get_country_code(ST_Centroid(pl.geometry))) as cc,
-                        pl.address->'postcode' as pc,
-                        COALESCE(plx.centroid, ST_Centroid(pl.geometry)) as centroid
-                      FROM place AS pl LEFT OUTER JOIN placex AS plx
-                             ON pl.osm_id = plx.osm_id AND pl.osm_type = plx.osm_type
-                    WHERE pl.address ? 'postcode' AND pl.geometry IS NOT null) xx
-                WHERE pc IS NOT null AND cc IS NOT null
-                ORDER BY cc, pc""")
-
-                collector = None
-
-                for country, postcode, x, y in cur:
-                    if collector is None or country != collector.country:
-                        if collector is not None:
-                            collector.commit(conn, analyzer, project_dir)
-                        collector = _PostcodeCollector(country, matcher.get_matcher(country))
-                        todo_countries.discard(country)
-                    collector.add(postcode, x, y)
-
-                if collector is not None:
-                    collector.commit(conn, analyzer, project_dir)
-
-            # Now handle any countries that are only in the postcode table.
-            for country in todo_countries:
-                fmt = matcher.get_matcher(country)
-                _PostcodeCollector(country, fmt).commit(conn, analyzer, project_dir)
-
+            # Backfill country_code column where required
+            conn.execute("""UPDATE place_postcode
+                              SET country_code = get_country_code(centroid)
+                              WHERE country_code is null
+                         """)
+            # Now update first postcode areas
+            _update_postcode_areas(conn, analyzer, matcher)
+            # Then fill with estimated postcode centroids from other info
+            _update_guessed_postcode(conn, analyzer, matcher, project_dir)
             conn.commit()
 
         analyzer.update_postcodes_from_db()
 
 
-def can_compute(dsn: str) -> bool:
+def _insert_postcode_areas(conn: Connection, country_code: str,
+                           extent: int, pcs: list[dict[str, str]]) -> None:
+    if pcs:
+        with conn.cursor() as cur:
+            cur.executemany(
+                pysql.SQL(
+                    """ INSERT INTO location_postcodes
+                            (osm_id, country_code, rank_search, postcode, centroid, geometry)
+                            SELECT osm_id, country_code, {}, %(out)s, centroid, geometry
+                            FROM place_postcode
+                            WHERE osm_type = 'R'
+                                  and country_code = {} and postcode = %(in)s
+                                  and geometry is not null
+                    """).format(pysql.Literal(_extent_to_rank(extent)),
+                                pysql.Literal(country_code)),
+                pcs)
+
+
+def _update_postcode_areas(conn: Connection, analyzer: AbstractAnalyzer,
+                           matcher: PostcodeFormatter) -> None:
+    """ Update the postcode areas made from postcode boundaries.
     """
-        Check that the place table exists so that
-        postcodes can be computed.
+    # first delete all areas that have gone
+    conn.execute(""" DELETE FROM location_postcodes pc
+                     WHERE pc.osm_id is not null
+                       AND NOT EXISTS(
+                              SELECT * FROM place_postcode pp
+                              WHERE pp.osm_type = 'R' and pp.osm_id = pc.osm_id
+                                    and geometry is not null)
+                """)
+    # now insert all in country batches, triggers will ensure proper updates
+    with conn.cursor() as cur:
+        cur.execute(""" SELECT country_code, postcode FROM place_postcode
+                        WHERE geometry is not null and osm_type = 'R'
+                        ORDER BY country_code
+                    """)
+        country_code = None
+        fmt = None
+        pcs = []
+        for cc, postcode in cur:
+            if country_code is None:
+                country_code = cc
+                fmt = matcher.get_matcher(country_code)
+            elif country_code != cc:
+                _insert_postcode_areas(conn, country_code,
+                                       matcher.get_postcode_extent(country_code), pcs)
+                country_code = cc
+                fmt = matcher.get_matcher(country_code)
+                pcs = []
+            assert fmt is not None
+
+            if (m := fmt.match(postcode)):
+                pcs.append({'out': fmt.normalize(m), 'in': postcode})
+
+        if country_code is not None and pcs:
+            _insert_postcode_areas(conn, country_code,
+                                   matcher.get_postcode_extent(country_code), pcs)
+
+
+def _update_guessed_postcode(conn: Connection, analyzer: AbstractAnalyzer,
+                             matcher: PostcodeFormatter, project_dir: Optional[Path]) -> None:
+    """ Computes artificial postcode centroids from the placex table,
+        potentially enhances it with external data and then updates the
+        postcodes in the table 'location_postcodes'.
+    """
+    # First get the list of countries that currently have postcodes.
+    # (Doing this before starting to insert, so it is fast on import.)
+    with conn.cursor() as cur:
+        cur.execute("""SELECT DISTINCT country_code FROM location_postcodes
+                        WHERE osm_id is null""")
+        todo_countries = {row[0] for row in cur}
+
+    # Next, get the list of postcodes that are already covered by areas.
+    area_pcs = defaultdict(set)
+    with conn.cursor() as cur:
+        cur.execute("""SELECT country_code, postcode
+                       FROM location_postcodes WHERE osm_id is not null
+                       ORDER BY country_code""")
+        for cc, pc in cur:
+            area_pcs[cc].add(pc)
+
+    # Create a temporary table which contains coverage of the postcode areas.
+    with conn.cursor() as cur:
+        cur.execute("DROP TABLE IF EXISTS _global_postcode_area")
+        cur.execute("""CREATE TABLE _global_postcode_area AS
+                       (SELECT ST_SubDivide(ST_Union(geometry)) as geometry
+                        FROM place_postcode WHERE geometry is not null)
+                    """)
+        cur.execute("CREATE INDEX ON _global_postcode_area USING gist(geometry)")
+    # Recompute the list of valid postcodes from placex.
+    with conn.cursor(name="placex_postcodes") as cur:
+        cur.execute("""
+            SELECT country_code, postcode, ST_X(centroid), ST_Y(centroid)
+              FROM (
+                (SELECT country_code, address->'postcode' as postcode, centroid
+                  FROM placex WHERE address ? 'postcode')
+                UNION
+                (SELECT country_code, postcode, centroid
+                 FROM place_postcode WHERE geometry is null)
+              ) x
+              WHERE not postcode like '%,%' and not postcode like '%;%'
+                    AND NOT EXISTS(SELECT * FROM _global_postcode_area g
+                                   WHERE ST_Intersects(x.centroid, g.geometry))
+              ORDER BY country_code""")
+
+        collector = None
+
+        for country, postcode, x, y in cur:
+            if collector is None or country != collector.country:
+                if collector is not None:
+                    collector.commit(conn, analyzer, project_dir)
+                collector = _PostcodeCollector(country, matcher.get_matcher(country),
+                                               matcher.get_postcode_extent(country),
+                                               exclude=area_pcs[country])
+                todo_countries.discard(country)
+            collector.add(postcode, x, y)
+
+        if collector is not None:
+            collector.commit(conn, analyzer, project_dir)
+
+    # Now handle any countries that are only in the postcode table.
+    for country in todo_countries:
+        fmt = matcher.get_matcher(country)
+        ext = matcher.get_postcode_extent(country)
+        _PostcodeCollector(country, fmt, ext,
+                           exclude=area_pcs[country]).commit(conn, analyzer, project_dir)
+
+    conn.execute("DROP TABLE IF EXISTS _global_postcode_area")
+
+
+def can_compute(dsn: str) -> bool:
+    """ Check that the necessary tables exist so that postcodes can be computed.
     """
     with connect(dsn) as conn:
-        return table_exists(conn, 'place')
+        return table_exists(conn, 'place_postcode')