TNSNAMES.ORA & SQLNET.ORA

What are tnsnames.ora and sqlnet.ora files ? And what are they used for ?

The 'tnsnames.ora' file functions in much the same way as the 'hosts' file in a Unix and PC environment. These text files provide the network addressing information to other systems on the network, allowing your system to find and communicate with other systems. The downside to this system is that anytime a system on the network changes its address everyone using this method needs to manually update their own 'tnsnames.ora' and/or 'hosts' file.

The 'sqlnet.ora' file provides the network address to the Oracle Name Server (ONS) for SQL*Net connections. ONS provides the same type of service as the campus Domain Name Server (DNS) does. When your system needs to talk with another system on the network, your system sends the name of the system it needs to talk to to the ONS server and the ONS server provides the network address to that system, allowing you to find that system and establish communications with it. The primary benefit of using ONS and DNS is that when a system changes its network address only the ONS or DNS server needs to be updated. All systems requesting a network address are given the new address and the user does not even know a change had happened.

DaFIS Transaction Processing (TP) is registered with the campus ONS system on campus and uses the ONS method rather then the 'tnsnames.ora' file.

Departments on campus that maintain their own Oracle Database and require their users to use 'tnsnames.ora' instead of ONS are encouraged to consider registering their system on the campus ONS server to eliminate possible downtime due to address changes in the future. For information on registering your system contact the Desktop Systems Group.

For departments or users that choose not to use ONS, DaFIS TP has provided a means to allow your DaFIS users to keep their 'tnsnames.ora' file.

Note: DaFIS TP will not update the 'tnsnames.ora' file. It is the responsibility of the department or user to modify their own 'tnsnames.ora' file to connect to DaFIS TP. To obtain the current settings needed to connect to DaFIS TP please send an email to dafishelp@ucdavis.edu.

The DaFIS Install program automatically installs 'sqlnet.ora' and 'DaFIS Info.txt' files in the '\Network\Admin\' directory of the '\orawin95' or '\orant' directory tree. If the program finds a file named 'DaFIS.txt' in the same directory it will ask the user for permission to rename the 'tnsnames.ora' file to 'tnsnames.dafis' and 'sqlnet.ora' file to 'sqlnet.dafis'. If permission is given it will rename the files and copy new 'sqlnet.ora' and 'DaFIS Info.txt' files to this directory. If permission is not given, no files will be changed.

Note: If your system was using the 'custom.txt' file it will be replaced with 'DaFIS.txt' to be compatible with the new DaFIS Update.