Oracle Net Services software provides the ability to define all the components of a distributed network, including all
- database servers,
- listeners, and
- database links.
This global definition is called a topology.
To support the topology, Oracle Net Services enables Oracle databases to connect to each other in a seamless fashion.
Connectivity is first established in Oracle by defining service names
in a special file. In Oracle Net Services,
a service name is a name that is used to uniquely identify each Oracle database.
Usually a service name is the same as the database name (ORACLE_SID), but it can be different.
The service name is translated by Oracle to obtain all the information it needs to connect to the remote database.
In the next lesson, we will continue our examination of Oracle's topology solution with a look at the role of database links in establishing database connectivity.
Each database is represented by one or more services and a service is identified by a service name, for example,
A client uses a service name to identify the database it must access.
The information about the database service and its location in the network is transparent to the client because the information needed for a connection is stored in a repository.
The repository is represented by one or more naming methods.
A naming method is a resolution method used by a client application to resolve a connect identifier to a connect descriptor when attempting to connect to a database service.
Oracle Net Services offers several types of naming methods that support localized configuration on each client, or centralized configuration that can be accessed by all clients in the network.
GUIs enable you to manage data stored in the naming methods.