19 lines
1.3 KiB
MySQL
19 lines
1.3 KiB
MySQL
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-- 05_inc_geography.sql — fleettickets · add a geography column for routing/distance
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-- ─────────────────────────────────────────────────────────────────────────────
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-- `geom` is geometry(Point,4326) — great for display, but distance on it is in
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-- planar degrees. For real-world routing ("nearest vehicle", radius search) we want
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-- geography, whose ST_Distance / ST_DWithin work in metres on the spheroid.
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--
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-- `geog` is a STORED generated column = geom::geography (the cast is IMMUTABLE), so
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-- it tracks geom automatically (incl. after geocode passes). GiST index supports
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-- ST_DWithin(geog, vehicle::geography, metres) and KNN nearest-neighbour ordering.
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-- Idempotent.
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-- ─────────────────────────────────────────────────────────────────────────────
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SET search_path = tickets, public;
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ALTER TABLE tickets.inc
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ADD COLUMN IF NOT EXISTS geog geography(Point, 4326) GENERATED ALWAYS AS (geom::geography) STORED;
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CREATE INDEX IF NOT EXISTS ix_inc_geog ON tickets.inc USING gist (geog);
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