===== Funktion für Datenbank-Trigger erstellen =====

__SQL/PL-Funktion erstellen__

  * Rückgabetyp: trigger
  * Programmiersprache: plpgsql

!! Argumente alle entfernen !!


Definition:

----

	BEGIN
		New.centroid = ST_Centroid( New.geography::geometry );
		IF GeometryType( New.geography ) = 'POLYGON' THEN
			IF ST_IsValid( ST_AsText(  New.geography ) ) = 't' THEN
				New.geography_area := ST_Area( New.geography );
				New.geography_perimeter := ST_Perimeter( New.geography );
			ELSE
				RAISE EXCEPTION 'Polygon intersection by column geography';
			END IF;
		ELSE
			New.geography_length := ST_Length( New.geography );
			IF ST_IsValid( ST_AsText(  New.geography_polygon ) ) = 't' THEN
				New.geography_area := ST_Area( New.geography_polygon );
				New.geography_perimeter := ST_Perimeter( New.geography_polygon );
			ELSE
				RAISE EXCEPTION 'Polygon intersection by column geography_polygon';
			END IF;
		END IF;
		Return New;
	END

----

Entspricht:
	UPDATE discovery SET centroid = ST_Centroid( New.geography::geometry ),
	geography_area = 5, geography_perimeter = 9, geography_length = 2 WHERE id=52

===== Neuen Datenbank-Trigger in phpPgAdmin anlegen =====


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