016 - Chapter 2. Name Resolution <p clas><script> function OpenWin(url, w, h) { if(!w) w = 400; if(!h) h = 300; window. open (url, "_new", "width=" + w + ",height=" + h + ",menubar=no,toobar=no,scrollbars=yes", true); } function Print() { window.focus(); if(window.print) { window.print(); window.setTimeout('window.close();',5000); } } </script></p>
Team-Fly
Oracle Net8 Configuration and Troubleshooting By Jonathan Gennick, Hugo Toledo
Table of Contents
Part I: How Net8 Works
Name resolution is the process of taking a net service name, which is a name you use when you connect to a database, and translating it to a specific database service, or database instance, on a specific host. One of the nice things about Net8 is that it provides location transparency to your applications by allowing you to connect to a database using a net service name. Net8 takes that net service name and puts it through a name resolution process in order to determine the following pieces of information:
The network address of the database server
The database service name or the instance name
The protocol to use for the connection
There may be other information associated with a net service name, but these items represent the primary pieces of information needed to connect to a database over a network.
Prior to release 8.1 of Net8, the term service name was used for what Oracle now calls a net service name . The name was changed so that Oracle could use the term service name to describe a database service. A Net8 service is now identified by a net service name.
Oracle currently supports the following five name resolution methods (each has its own set of advantages and disadvantages):
Local naming ( tnsnames.ora files)
Uses a file called tnsnames.ora on each client to translate net service names .
Directory naming (LDAP)
Is really another form of centralized name management, but it involves the use of an LDAP directory as a repository for name definitions.
Centralized naming (Oracle Names)
Involves the use of Oracle Namesname resolution software specifically developed by Oracle to enable centralized management of net service names.
Host naming (DNS, TCP/IP only)
Is new in Oracle8 i , and allows you to access a database by specifying only the server name.
External naming (NIS, NDS, CDS)
Allows you to use a non-Oracle directory serviceNovell Directory Services (NDS), for exampleto manage net service names.
