16.15.1.Programmatic Manipulation of
Geometries in RDF
The ttlp function is
the preferred way of inserting geometries. The more are inserted at
one time, the more efficient the operation is. This loader function
will also deal with cluster message optimization.
A geometry occurring in an RDF quad object is a member of the
RDF box data type. This data type stands for a typed RDF literal.
The type of all geometries is 256. This is mapped to a URI in the
RDF_DATATYPE system table.
A geometry does not occur directly in the object position of a
quad. It is referenced by an id that is stored in the RDF typed
literal box and references RO_ID of the RDF_OBJ system table. To
translate a geometry into a RDF box that can be stored, do as in
the example below:
The DB.DBA.RDF_GEO_ADD function looks if an identical geometry
already exists and if so assigns the existing id to it. If the
geometry is new, it gets a new ID and is stored in the RDF literals
table RDF_OBJ. At this time it is also automatically inserted into
the RDF geometry index.
In a cluster situation one should use the dpipe mechanism for
inserting into RDF quad so as to get large numbers of inserts into
a single message. This is essential for performance.