1.7 Topology Metadata Views

There are two sets of topology metadata views for each schema (user): xxx_SDO_TOPO_INFO and xxx_SDO_TOPO_METADATA, where xxx can be USER or ALL. These views are read-only to users; they are created and maintained by Oracle Spatial.

The xxx_SDO_TOPO_METADATA views contain the most detailed information, and each xxx_SDO_TOPO_INFO view contains a subset of the information in its corresponding xxx_SDO_TOPO_METADATA view.

• xxx_SDO_TOPO_INFO Views
  
• xxx_SDO_TOPO_METADATA Views
  

1.7.1 xxx_SDO_TOPO_INFO Views

The following views contain basic information about topologies:

• USER_SDO_TOPO_INFO contains topology information for all feature tables owned by the user.

• ALL_SDO_TOPO_INFO contains topology information for all feature tables on which the user has SELECT permission.

The USER_SDO_TOPO_INFO and ALL_SDO_TOPO_INFO views contain the same columns, as shown Table 1-8. (The columns are listed in their order in the view definition.)

Table 1-8 Columns in the xxx_SDO_TOPO_INFO Views

Column Name	Data Type	Purpose
OWNER	VARCHAR2	Owner of the topology
TOPOLOGY	VARCHAR2	Name of the topology
TOPOLOGY_ID	NUMBER	ID number of the topology
TOLERANCE	NUMBER	Tolerance value associated with topology geometries in the topology. (Tolerance is explained in Tolerance in the Topology Data Model.)
SRID	NUMBER	Coordinate system (spatial reference system) associated with all topology geometry layers in the topology. Is null if no coordinate system is associated; otherwise, it contains a value from the SRID column of the MDSYS.CS_SRS table (described in Oracle Spatial Developer's Guide).
TABLE_SCHEMA	VARCHAR2	Name of the schema that owns the table containing the topology geometry layer column
TABLE_NAME	VARCHAR2	Name of the table containing the topology geometry layer column
COLUMN_NAME	VARCHAR2	Name of the column containing the topology geometry layer data
TG_LAYER_ID	NUMBER	ID number of the topology geometry layer
TG_LAYER_TYPE	VARCHAR2	Contains one of the following: POINT, LINE, CURVE, POLYGON, or COLLECTION. (LINE and CURVE have the same meaning.)
TG_LAYER_LEVEL	NUMBER	Hierarchy level number of this topology geometry layer. (Topology geometry layer hierarchy is explained in Topology Geometry Layer Hierarchy.)
CHILD_LAYER_ID	NUMBER	ID number of the topology geometry layer that is the child layer of this layer in the topology geometry layer hierarchy. Null if this layer has no child layer or if the topology does not have a topology geometry layer hierarchy. (Topology geometry layer hierarchy is explained in Topology Geometry Layer Hierarchy.)
DIGITS_RIGHT_OF_DECIMAL	NUMBER	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) are automatically snapped (truncated) to the number of digits right of the decimal. Default: 16.

1.7.2 xxx_SDO_TOPO_METADATA Views

The following views contain detailed information about topologies:

• USER_SDO_TOPO_METADATA contains topology information for all tables owned by the user.

• ALL_SDO_TOPO_METADATA contains topology information for all tables on which the user has SELECT permission.

The USER_SDO_TOPO_METADATA and ALL_SDO_TOPO_METADATA views contain the same columns, as shown Table 1-9. (The columns are listed in their order in the view definition.)

Table 1-9 Columns in the xxx_SDO_TOPO_METADATA Views

Column Name	Data Type	Purpose
OWNER	VARCHAR2	Owner of the topology
TOPOLOGY	VARCHAR2	Name of the topology
TOPOLOGY_ID	NUMBER	ID number of the topology
TOLERANCE	NUMBER	Tolerance value associated with topology geometries in the topology. (Tolerance is explained in Tolerance in the Topology Data Model.)
SRID	NUMBER	Coordinate system (spatial reference system) associated with all topology geometry layers in the topology. Is null if no coordinate system is associated; otherwise, contains a value from the SRID column of the MDSYS.CS_SRS table (described in Oracle Spatial Developer's Guide).
TABLE_SCHEMA	VARCHAR2	Name of the schema that owns the table containing the topology geometry layer column
TABLE_NAME	VARCHAR2	Name of the table containing the topology geometry layer column
COLUMN_NAME	VARCHAR2	Name of the column containing the topology geometry layer data
TG_LAYER_ID	NUMBER	ID number of the topology geometry layer
TG_LAYER_TYPE	VARCHAR2	Contains one of the following: POINT, LINE, CURVE, POLYGON, or COLLECTION. (LINE and CURVE have the same meaning.)
TG_LAYER_LEVEL	NUMBER	Hierarchy level number of this topology geometry layer. (Topology geometry layer hierarchy is explained in Topology Geometry Layer Hierarchy.)
CHILD_LAYER_ID	NUMBER	ID number of the topology geometry layer that is the child layer of this layer in the topology geometry layer hierarchy. Null if this layer has no child layer or if the topology does not have a geometry layer hierarchy. (Topology geometry layer hierarchy is explained in Topology Geometry Layer Hierarchy.)
NODE_SEQUENCE	VARCHAR2	Name of the sequence containing the next available node ID number
EDGE_SEQUENCE	VARCHAR2	Name of the sequence containing the next available edge ID number
FACE_SEQUENCE	VARCHAR2	Name of the sequence containing the next available face ID number
TG_SEQUENCE	VARCHAR2	Name of the sequence containing the next available topology geometry ID number
DIGITS_RIGHT_OF_DECIMAL	NUMBER	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) are automatically snapped (truncated) to the number of digits right of the decimal. Default: 16