ORACLE NetworkTopology

    The Oracle network architecture encompasses many components - all of which neatly corresponds to the OSI networking model (see below Figure oraclenw1.jpg). This architecture enables Oracle client and server applications to transparently communicate over protocols such as TCP/IP. The session protocol that interfaces between the applications (Oracle Call Interface, or OCI, on the client and Oracle Program Interface, or OPI, on the server) and the network layer is known as Net8 (Net9), and before that SQL*Net. Between the OCI/OPI and Net8 layer is a presentation protocol called Two-Task Common (TTC) that is responsible for character set and data type conversion differences between the client and the server. The Net8 session protocol has three components - the Net Foundation and Routing/Naming/Auth and TNS - the last two making up Protocol Support. Supported transport protocols include TCP/IP, with or without TCP, Named Pipes and Sockets Direct Protocol (SDP), which enables communication over Infiband high-speed networks. Underpinning all of this is the Transparent Network Substrate protocol, also known as TNS. The task of TNS is to select the Oracle Protocol Adapter, wrapping the communication in one of the supported transport protocols.

        

           Main data dictionary view of network model is USER_SDO_NETWORK_METADATA which is in the user MDSYS", where "MD" stands for "Multi Dimensional" .

There are two  types of Network

1) LOGICAL
2) SPATIAL

 Among Spatial Netwrok there are 3 sub classification
  
  a) SDO Geometry
  b) LRS Geometry
  c) Topology Geometry
 
 LOGICAL
 --------

A network data model for representing capabilities of objects (modeled as nodes and links) in a network.


The network data model provides PL/SQL procedures (package SDO_NET) to simplify network creation and management.
The default values for network table names, column names, and metadata are as follows
Node table name: _NODE$
Link table name: _LINK$
Path table name: _PATH$ (only if the network contains paths)
Path Link table name: _PLINK$ (only if a path table is created; contains a row for
each link in each path in the network)


 Step 1:

    EXECUTE SDO_NET.CREATE_LOGICAL_NETWORK('NET_TEST'-- network name
  , 1 -- no of hierarchy level
  , FALSE  -- directed link?
  , FALSE  -- no with cost?
  );
 
 Step 2:

  Populate the node and link tables.
 
Step 3:

  Validate the network. select  SDO_NET.VALIDATE_NETWORK('NET_TEST') from dual ; 


During network creation if we  set cost parameter as TRUE ie :(  EXECUTE SDO_NET.CREATE_LOGICAL_NETWORK('NET_TEST', 1, FALSE , TRUE);  )
 Then in  _NODE$ table COST named  field will be created , and if  directlink parameter is set as TRUE then in _LINK$ table Biridected named field will be created .

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