When you create or rebuild a spatial index, you can ensure that all geometries that are in the table or that are inserted later are of a specified geometry type. To constrain the data to a geometry type in this way, use the layer_gtype keyword in the PARAMETERS clause of the CREATE INDEX or ALTER INDEX REBUILD statement, and specify a value from the Geometry Type column in SDO_GTYPE. For example, to constrain spatial data in a layer to polygons:
CREATE INDEX cola_spatial_idx
ON cola_markets(shape)
INDEXTYPE IS MDSYS.SPATIAL_INDEX
PARAMETERS ('layer_gtype=POLYGON');
The geometry types in SDO_GTYPE are considered as a hierarchy when data is checked:
The MULTI forms include the regular form also. For example, specifying 'layer_gtype=MULTIPOINT' allows the layer to include both POINT and MULTIPOINT geometries.
COLLECTION allows the layer to include all types of geometries.