+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
"""
Functions for database migration to newer software versions.
"""
ON location_property_tiger
USING btree(parent_place_id)
INCLUDE (startnumber, endnumber) """)
+
+
+@_migration(4, 0, 99, 1)
+def create_interpolation_index_on_place(conn, **_):
+ """ Create idx_place_interpolations for lookup of interpolation lines
+ on updates.
+ """
+ with conn.cursor() as cur:
+ cur.execute("""CREATE INDEX IF NOT EXISTS idx_place_interpolations
+ ON place USING gist(geometry)
+ WHERE osm_type = 'W' and address ? 'interpolation'""")
+
+
+@_migration(4, 0, 99, 2)
+def add_step_column_for_interpolation(conn, **_):
+ """ Add a new column 'step' to the interpolations table.
+
+ Also convers the data into the stricter format which requires that
+ startnumbers comply with the odd/even requirements.
+ """
+ with conn.cursor() as cur:
+ # Mark invalid all interpolations with no intermediate numbers.
+ cur.execute("""UPDATE location_property_osmline SET startnumber = null
+ WHERE endnumber - startnumber <= 1 """)
+ # Align the start numbers where odd/even does not match.
+ cur.execute("""UPDATE location_property_osmline
+ SET startnumber = startnumber + 1,
+ linegeo = ST_LineSubString(linegeo,
+ 1.0 / (endnumber - startnumber)::float,
+ 1)
+ WHERE (interpolationtype = 'odd' and startnumber % 2 = 0)
+ or (interpolationtype = 'even' and startnumber % 2 = 1)
+ """)
+ # Mark invalid odd/even interpolations with no intermediate numbers.
+ cur.execute("""UPDATE location_property_osmline SET startnumber = null
+ WHERE interpolationtype in ('odd', 'even')
+ and endnumber - startnumber = 2""")
+ # Finally add the new column and populate it.
+ cur.execute("ALTER TABLE location_property_osmline ADD COLUMN step SMALLINT")
+ cur.execute("""UPDATE location_property_osmline
+ SET step = CASE WHEN interpolationtype = 'all'
+ THEN 1 ELSE 2 END
+ """)
+
+
+@_migration(4, 0, 99, 3)
+def add_step_column_for_tiger(conn, **_):
+ """ Add a new column 'step' to the tiger data table.
+ """
+ with conn.cursor() as cur:
+ cur.execute("ALTER TABLE location_property_tiger ADD COLUMN step SMALLINT")
+ cur.execute("""UPDATE location_property_tiger
+ SET step = CASE WHEN interpolationtype = 'all'
+ THEN 1 ELSE 2 END
+ """)