5.2 Main Steps in Using the Network Data Model

This topic summarizes the main steps for working with the Network Data Model feature in Oracle Spatial. It refers to important concepts, structures, and operations that are described in detail in other topics.

There are two basic approaches to creating a network:

• Let Spatial perform most operations, using procedures with names in the form CREATE_<network-type>_NETWORK.

• Perform the operations yourself: create the necessary network tables and update the network metadata.

With each approach, you must insert the network data into the network tables. You can then use the Network Data Model PL/SQL and Java application programming interfaces (APIs) to update the network and perform other operations. (The PL/SQL and Java APIs are described in Network Data Model Application Programming Interface.)

• Letting Spatial Perform Most Operations
  
• Performing the Operations Yourself
  

5.2.1 Letting Spatial Perform Most Operations

To create a network by letting Spatial perform most of the necessary operations, follow these steps:

1. Create the network using a procedure with a name in the form CREATE_<network-type>_NETWORK, where <network-type> reflects the type of network that you want to create:

   • SDO_NET.CREATE_SDO_NETWORK for a spatial network with non-LRS SDO_GEOMETRY objects

   • SDO_NET.CREATE_LRS_NETWORK for a spatial network with LRS SDO_GEOMETRY objects

   • SDO_NET.CREATE_TOPO_NETWORK for a spatial network with topology geometry (SDO_TOPO_GEOMETRY) objects

   • SDO_NET.CREATE_LOGICAL_NETWORK for a logical network that does not contain spatial information

   Each of these procedures creates the necessary Network Data Model tables (described in Network Data Model Tables) and inserts a row with the appropriate network metadata information into the xxx_SDO_NETWORK_METADATA views (described in xxx_SDO_NETWORK_METADATA Views).

   Each procedure has two formats: one format creates all Network Data Model tables using default names for the tables and certain columns, and other format lets you specify names for the tables and certain columns. The default names for the Network Data Model tables are <network-name>_NODE$, <network-name>_LINK$, <network-name>_PATH$, and <network-name>_PLINK$. The default name for cost columns in the Network Data Model tables is COST, and the default name for geometry columns is GEOMETRY.

2. Insert data into the node and link tables, and if necessary into the path and path-link tables. (The node, link, path, and path-link tables are described in Network Data Model Tables.)
3. Validate the network, using the SDO_NET.VALIDATE_NETWORK function.
4. For a spatial (SDO or LRS) network, insert the appropriate information into the USER_SDO_GEOM_METADATA view, and create spatial indexes on the geometry columns.

   If you plan to use a view as a node, link, or path table, you must specify the view name for the TABLE_NAME column value when you insert information about the node, link, or path table in the USER_SDO_GEOM_METADATA view.

5.2.2 Performing the Operations Yourself

To create a network by performing the necessary operations yourself, follow these steps:

1. Create the node table, using the SDO_NET.CREATE_NODE_TABLE procedure.
2. Insert data into the node table.
3. Create the link table, using the SDO_NET.CREATE_LINK_TABLE procedure.
4. Insert data into the link table.
5. Optionally, create the path table, using the SDO_NET.CREATE_PATH_TABLE procedure.
6. If you created the path table, create the path-link table, using the SDO_NET.CREATE_PATH_LINK_TABLE procedure.
7. If you created the path table and if you want to create paths, insert data into the table.
8. If you inserted data into the path table, insert the appropriate rows into the path-link table.
9. Insert a row into the USER_SDO_NETWORK_METADATA view with information about the network. (The USER_SDO_NETWORK_METADATA view is described in xxx_SDO_NETWORK_METADATA Views.)

   If you plan to use a view as a node, link, path, or path-link table, you must specify the view name for the relevant columns when you insert information about the network in the USER_SDO_NETWORK_METADATA view.

10. For a spatial (SDO or LRS) network, insert the appropriate information into the USER_SDO_GEOM_METADATA view, and create spatial indexes on the geometry columns.

    If you plan to use a view as a node, link, or path table, you must specify the view name for the TABLE_NAME column value when you insert information about the node, link, or path table in the USER_SDO_GEOM_METADATA view.

11. Validate the network, using the SDO_NET.VALIDATE_NETWORK function.

You can change the sequence of some of these steps. For example, you can create both the node and link tables first, and then insert data into each one; and you can insert the row into the USER_SDO_NETWORK_METADATA view before you create the node and link tables.