Listener (Listener)
Oracle listener is a network service based on the service side, mainly for links to listen for client requests made to the database server.
Local service name (Tnsname)
Link Oracle client and server is issued by a client requests a link from the server to the client listener requests are legitimate link to check if the link request is valid, connection, or refuse the link.
Oracle Net Link mode
Link database server (both client and server on the same server)
Link way: CONNECT username / password
All non-server database connection
Listener server startup process
The client connection string to parse through and so Tnsname or Easy connect or LDAP name resolution mode, once the link is successful, even if the Listener service stops, does not affect the session connected, you can not build a new answer.
Client to the server to establish a session process
connet username/password@netservername
例：conn scott/tiger@orcl
Username: scott
Password: tiger
/: Division account secret
@: User process network connection required
orcl: link identifier
Link descriptor
Use one format to describe the link information contains ip, the service name and port number of the database.
orcl =: Network service name, the database alias.
(ADDRESS = (PROTOCOL = TCP) (HOST = 192.168.1.2) (PORT = 1521)): contains the IP address, port number 1521.
(SERVICE_NAME = orcl): name of the server database service
Service name server_name
Link to client service name server instance, you can specify one or more parameters for the service name. This parameter is introduced from 9i, server_name may be used instead of sid, after 9i, the Oracle recommended instead server_name sid to distinguish between different user connections by defining a different service name. In the server, you can define a number of different service name to distinguish the different user connections.
Based on the same database, you can define different service name to distinguish the different usage.
例：server_name = sales.orcl,oa.orcl
Hr associated with a user can connect through hr service, with oa the relevant user can be connected through the service name oa.
Common configuration file
ldpq.ora -> used to configure the LDAP directory name resolution.
cman.ora -> Management Parameters for configuring Oracle
tnsname.ora - local name> is used to configure local clients or remote clients resolve
Registration information> is used to configure the Listener - listener.ora
sqlnet.ora -> analytical methods used to configure the server or client support
Common configuration files path: $ ORACLE_HOME / network / admin
If ASM file mode, use the grid users.