Mercurial > gemma
diff schema/updates/1431/01.prevent_equal_fairway_areas.sql @ 5095:e21cbb9768a2
Prevent duplicate fairway areas
In principal, there can be only one or no fairway area at each point
on the map. Since polygons from real data will often be topologically
inexact, just disallow equal geometries. This will also help to
avoid importing duplicates with concurrent imports, once the history
of fairway dimensions will be preserved.
| author | Tom Gottfried <tom@intevation.de> |
|---|---|
| date | Wed, 25 Mar 2020 18:10:02 +0100 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/schema/updates/1431/01.prevent_equal_fairway_areas.sql Wed Mar 25 18:10:02 2020 +0100 @@ -0,0 +1,4 @@ +CREATE CONSTRAINT TRIGGER fairway_dimensions_area_unique + AFTER INSERT OR UPDATE OF area, staging_done + ON waterway.fairway_dimensions + FOR EACH ROW EXECUTE FUNCTION prevent_st_equals('area', 'staging_done');