MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
A Curve is a one-dimensional geometry,
usually represented by a sequence of points. Particular
subclasses of Curve define the type of
interpolation between points. Curve is a
noninstantiable class.
Curve
Properties
A Curve has the coordinates of its
points.
A Curve is defined as a one-dimensional
geometry.
A Curve is simple if it does not pass
through the same point twice, with the exception that a
curve can still be simple if the start and end points are
the same.
A Curve is closed if its start point is
equal to its endpoint.
The boundary of a closed Curve is
empty.
The boundary of a nonclosed Curve
consists of its two endpoints.
A Curve that is simple and closed is a
LinearRing.