Files
Nominatim/test/bdd/steps/table_compare.py
2021-01-05 16:00:48 +01:00

63 lines
2.1 KiB
Python

"""
Functions to facilitate accessing and comparing the content of DB tables.
"""
import re
ID_REGEX = re.compile(r"(?P<typ>[NRW])(?P<oid>\d+)(:(?P<cls>\w+))?")
class NominatimID:
""" Splits a unique identifier for places into its components.
As place_ids cannot be used for testing, we use a unique
identifier instead that is of the form <osmtype><osmid>[:<class>].
"""
def __init__(self, oid):
self.typ = self.oid = self.cls = None
if oid is not None:
m = ID_REGEX.fullmatch(oid)
assert m is not None, \
"ID '{}' not of form <osmtype><osmid>[:<class>]".format(oid)
self.typ = m.group('typ')
self.oid = m.group('oid')
self.cls = m.group('cls')
def __str__(self):
if self.cls is None:
return self.typ + self.oid
return '{self.typ}{self.oid}:{self.cls}'.format(self=self)
def query_osm_id(self, cur, query):
""" Run a query on cursor `cur` using osm ID, type and class. The
`query` string must contain exactly one placeholder '{}' where
the 'where' query should go.
"""
where = 'osm_type = %s and osm_id = %s'
params = [self.typ, self. oid]
if self.cls is not None:
where += ' and class = %s'
params.append(self.cls)
return cur.execute(query.format(where), params)
def query_place_id(self, cur, query):
""" Run a query on cursor `cur` using the place ID. The `query` string
must contain exactly one placeholder '%s' where the 'where' query
should go.
"""
pid = self.get_place_id(cur)
return cur.execute(query, (pid, ))
def get_place_id(self, cur):
""" Look up the place id for the ID. Throws an assertion if the ID
is not unique.
"""
self.query_osm_id(cur, "SELECT place_id FROM placex WHERE {}")
assert cur.rowcount == 1, \
"Place ID {!s} not unique. Found {} entries.".format(self, cur.rowcount)
return cur.fetchone()[0]