file is a text file used by Net8 to
resolve net service names when local naming is used. By default,
tnsnames.ora resides in the
$ORACLE_HOME/network /admin directory.
Understanding the syntax used for
entries is a key requirement for using almost any Net8 functionality.
The same syntax used to define net service names in
tnsnames.ora is also used to define net service
names when Oracle Names or an LDAP-based repository such as the
Oracle Internet Directory is used for name resolution.
The primary purpose of an entry in the
tnsnames.ora file is to link a net service name
with a set of attributes that can be used to connect a client to an
Oracle database. These attributes are loosely organized into the
following two major categories:
The protocol address or addresses
The connection data
The protocol address for a net service name points the client to the physical server on which a database instance is running. You might also refer to a protocol address as a network address. The connection data identifies the specific database instance or service, running on that server, to which the client is to connect.
Taken together, the combination of a protocol address and connection data is referred to as a description . Most net service name definitions are fairly simple and consist of just one description. Here’s an example:
DONNA.GENNICK.ORG = (DESCRIPTION = (ADDRESS_LIST ...