CurvePolygon Data Type
The CurvePolygon type is a collection of geometries of types Polygon, CircularString and CompoundCurve. The Polygon requirement that starting coordinates are the same as ending coordinates is still the same as well as any other requirement of Polygons.
Examples:
Without specifying SRID:
CREATE TABLE cpolys (name VARCHAR(30), cpoly CURVEPOLYGON);
With specifying SRID:
CREATE TABLE cpolys (name VARCHAR(30), cpoly CURVEPOLYGON SRID 4326);
Show a line followed by an arc:
CREATE TABLE cpolys (id INT, cpoly CURVEPOLYGON);
INSERT INTO cpolys (id, cpoly) VALUES (1, GeomFromText('CURVEPOLYGON((4 0, 4 -4, 0 -4, 0 0), CIRCULARSTRING(0 0, 2 2, 4 0))'));