In order for an Oracle table to be recognized as a feature, the following criteria must also be met:

• The feature table must have a primary key constraint consisting of a single numeric or string/character column to represent the feature ID. This primary key is required to enable versioning using the standard versioning system of the Oracle Workspace Manager. A composite primary key can also be used.
• The table must have a geometric (SDO_GEOMETRY) column specifying the feature geometry, and this geometry column must be registered in the Oracle Spatial metadata table (ALL_SDO_GEOM_METADATA or the related USER_SDO_GEOM_METADATA view for the user).
• The table fields must be of a common type, not a user defined type.
• Geometry must be of similar types, meaning all geometries must be of point, line, or polygon type and not a mixture of these.

  To determine if a table contains more than one geometry type:

  SQL > select p.geometry.sdo_gtype, count(*) from your_table p group by p.geometry.sdo_gtype;

  GTYPE = 2001 or 3001 = points

  GTYPE = 2002 or 3002 = lines

  GTYPE = 2003 or 3003 = polygons