The Oracle Transparent Network Substrate (TNS) is a file used by the Oracle database to establish a connection to a remote database. This file contains all the necessary information for the database to connect to the desired location. In this article, we will discuss the details of the Oracle TNS Names File and how to identify and locate it.
The TNS Names File is a configuration file that stores the network addresses of all the databases that the Oracle database can connect to. It acts as a directory for the database to find the correct database to establish a connection. This file is essential for any Oracle database installation and is located in the Oracle Home directory.
To identify the TNS Names File, we first need to know the location of the Oracle Home directory. This directory contains all the files and folders related to the Oracle database. The location of the Oracle Home directory will vary depending on the operating system and the version of the Oracle database. However, it is usually located in the ORACLE_HOME environment variable.
Once we have located the Oracle Home directory, we can find the TNS Names File in the Network/Admin folder. This folder contains all the network-related configuration files, including the TNS Names File. The file is usually named "tnsnames.ora" and can be opened with any text editor.
The TNS Names File follows a specific syntax and contains a list of connection descriptors. Each descriptor contains information such as the database name, network address, and protocol used for the connection. These descriptors are used by the database to establish a connection to the desired database.
The structure of a connection descriptor in the TNS Names File is as follows:
<Database Name> =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = <Protocol>) (HOST = <Host>) (PORT = <Port>))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = <Service Name>)
)
)
Let's break down the above structure to understand it better. The first line contains the name of the database that we want to connect to. This name can be any alphanumeric characters and is used to identify the database in the TNS Names File.
The next few lines contain the description of the connection. This includes the network address of the database, which is specified in the ADDRESS parameter. The PROTOCOL parameter defines the network protocol used for the connection, such as TCP/IP or IPC. The HOST parameter specifies the hostname or IP address of the database server, and the PORT parameter specifies the port number on which the database is listening for connections.
The CONNECT_DATA section contains the information required to establish the connection. The SERVER parameter specifies whether the connection is dedicated or shared. A dedicated connection means that the database has a dedicated process for handling the connection, while a shared connection means that multiple connections share the same process. The SERVICE_NAME parameter specifies the name of the database service that the connection will use.
In the TNS Names File, we can have multiple connection descriptors for different databases. This allows the Oracle database to connect to multiple databases using the same file.
In conclusion, the Oracle TNS Names File is a crucial component of the Oracle database that stores network addresses of all the databases that the database can connect to. It is located in the Network/Admin folder of the Oracle Home directory and follows a specific syntax for connection descriptors. By understanding the structure of the file, we can easily identify and locate it and make any necessary changes for successful database connections.
