Each instance needs its own gateway System ID (SID).

Multiple Informix Databases Example: Configuring the GatewayД¬hoose One System ID for Each Informix DatabaseДЄ separate instance of the gateway is needed for each Informix database. SQL> CREATE PUBLIC DATABASE LINK dblink CONNECT TOДў ' user' IDENTIFIED BY 'password' USING 'tns_name_entry'

A public database link is the most common of database links. To access the Informix server, you must create a database link. If you want to close a database link during a session, you can do so with the ALTER SESSION statement. Another session or user can access the same database link and get a distinct connection to the gateway and Informix database.Дatabase links are active for the duration of a gateway session.

The connection remains established until the Oracle session ends. In this context, a connection refers to the connection between the Oracle database and the gateway. The gateway accepts connections only from the Oracle database.ДЄ connection to the gateway is established through a database link when it is first used in an Oracle session. The Oracle client and the Oracle database can reside on different machines. Specifies that this connect descriptor connects to a non-Oracle system.ДЄny Oracle client connected to the Oracle database can access Informix data through the gateway. See 'Configure Oracle Net Listener for the Gateway' for more information. Specifies the SID of the gateway and matches the SID specified in the listener.ora file of the Oracle Net Listener that is listening for the gateway. See 'Syntax of listener.ora File Entries'. The Oracle Net Listener's port number can be found in the listener.ora file used by the Oracle Net Listener. Matches the port number used by the Oracle Net Listener that is listening for the gateway. Specifies the machine where the gateway is running. Is the TCP protocol used for TCP/IP connections. Note: The sqlnet.ora file is typically stored in $ORACLE_HOME/network/admin. Is the description of the object to connect to as specified when creating the database link, such as dg4ifmx.Д¬heck the sqlnet.ora file for the following parameter setting: HS_FDS_CONNECT_INFO= host_name: port_number/ server_name/ database_name The syntax for HS_FDS_CONNECT_INFO is as follows: The default initialization parameter file already has an entry for this parameter. The most important parameter is the HS_FDS_CONNECT_INFO, which describes the connection to the non-Oracle system. Changes made to the initialization parameters only take effect in the next gateway session. Refer to Appendix C, 'Initialization Parameters' for the complete list of initialization parameters that can be set. This default initialization parameter file is sufficient for starting the gateway, verifying a successful installation, and running the demonstration scripts.ДЄ number of initialization parameters can be used to modify the gateway behavior. If you are not using dg4ifmx as the gateway SID, you must rename the initialization parameter file using the SID you chose in the preceding step 'Choose a System Identifier for the Gateway'. This initialization file is for the default gateway SID. Where $ORACLE_HOME is the directory under which the gateway is installed. During installation, the following default initialization parameter file is created: $ORACLE_HOME/dg4ifmx/admin/initdg4ifmx.ora

The initialization parameter file must be available when the gateway is started. Customize the Initialization Parameter File

Informix odbc port number