SDO_TOPO.CREATE

Format

SDO_TOPO.CREATE_TOPOLOGY(     
  topology                 IN VARCHAR2,      
  tolerance                IN NUMBER,      
  srid                     IN NUMBER DEFAULT NULL,      
  node_table_storage       IN VARCHAR2 DEFAULT NULL,      
  edge_table_storage       IN VARCHAR2 DEFAULT NULL,      
  face_table_storage       IN VARCHAR2 DEFAULT NULL,      
  history_table_storage    IN VARCHAR2 DEFAULT NULL.      
  digits_right_of_decimal  IN VARCHAR2 DEFAULT 16);

Description

Creates a topology.

Parameters

topology

Name of the topology to be created. Must not exceed 20 characters.

tolerance

Tolerance value associated with topology geometries in the topology. (Tolerance is explained in Tolerance in the Topology Data Model.)

srid

Coordinate system (spatial reference system) associated with all topology geometry layers in the topology. The default is null: no coordinate system is associated; otherwise, it must be a value from the SRID column of the SDO_COORD_REF_SYS table (described in Oracle Spatial Developer's Guide).

node_table_storage

Physical storage parameters used internally to create the <topology-name>_NODE$ table (described in Node Information Table). Must be a valid string for use with the CREATE TABLE statement. For example: TABLESPACE tbs_3 STORAGE (INITIAL 100K NEXT 200K). If you do not specify this parameter, the default physical storage values are used.

edge_table_storage

Physical storage parameters used internally to create the <topology-name>_EDGE$ table (described in Edge Information Table). Must be a valid string for use with the CREATE TABLE statement. For example: TABLESPACE tbs_3 STORAGE (INITIAL 100K NEXT 200K). If you do not specify this parameter, the default physical storage values are used.

face_table_storage

Physical storage parameters used internally to create the <topology-name>_FACE$ table (described in Face Information Table). Must be a valid string for use with the CREATE TABLE statement. For example: TABLESPACE tbs_3 STORAGE (INITIAL 100K NEXT 200K). If you do not specify this parameter, the default physical storage values are used.

history_table_storage

Physical storage parameters used internally to create the <topology-name>_HISTORY$ table (described in History Information Table. Must be a valid string for use with the CREATE TABLE statement. For example: TABLESPACE tbs_3 STORAGE (INITIAL 100K NEXT 200K). If you do not specify this parameter, the default physical storage values are used.

digits_right_of_decimal

The number of digits permitted to the right of the decimal point in the expression of any coordinate position when features are added to an existing topology. All incoming features (those passed as arguments to the addLinearGeometry, addPolygonGeometry, or addPointGeometry method in the Java API or the equivalent PL/SQL subprograms) will be automatically snapped (truncated) to the number of digits right of the decimal that is specified in this parameter. The default is 16.

This value should be set to match the last digit right of the decimal point that is considered valid based on the accuracy of the incoming data. This mechanism is provided to improve the stability of the computational geometry during the feature insertion process, and to minimize the creation of sliver polygons and other undesired results.

Usage Notes

This procedure creates the <topology-name>_EDGE$, <topology-name>_NODE$, <topology-name>_FACE$, and <topology-name>_HISTORY$ tables, which are described in Topology Data Model Tables, and it creates B-tree indexes on the primary keys of these tables. This procedure also creates the metadata for the topology.

In the srid parameter, you can specify a geodetic coordinate system; however, all Spatial internal operations on the topology will use Cartesian (not geodetic) arithmetic operations. (Geodetic and non-geodetic coordinate systems are discussed in Oracle Spatial Developer's Guide.)

Node, edge, face, and history tables are created without partitions; however, you can alter any of these tables to make it partitioned. You can also create a partitioned spatial index on a partitioned table, as explained in Oracle Spatial Developer's Guide.

This procedure automatically performs a commit operation, and therefore it cannot be rolled back. To delete the topology that you just created, call the SDO_TOPO.DROP_TOPOLOGY procedure.

An exception is raised if the topology already exists.

Examples

The following example creates a topology named CITY_DATA. The spatial geometries in this topology have a tolerance value of 0.5 and use the WGS 84 coordinate system (longitude and latitude, SRID value 8307). (The example refers to definitions and data from Topology Built from Topology Data.)

EXECUTE SDO_TOPO.CREATE_TOPOLOGY('CITY_DATA', 0.5, 8307);