The Driver Manager on UNIX and Linux supports file data sources. The advantage of a file data source is that it can be stored on a server and accessed by other machines, Windows, UNIX, or Linux. See "Configuring and connecting to data sources" for a general description of ODBC data sources on Windows, UNIX, and Linux platforms.

A file data source is simply a text file that contains connection information. It can be created with a text editor. The file normally has an extension of .dsn.

For example, a file data source for the driver would be similar to the following:

[ODBC]
Driver=DataDirect 8.0 Greenplum Wire Protocol
...  
HostName=MyServer
...
PortNumber=5432
...
Database=Payroll
...
LogonID=jsmith
...
Password=secret
...
Note: The LogonID and Password options are not required to be stored in the data source. They can also be sent separately by the application using the SQLConnect ODBC API. For SQLDriverConnect and SQLBrowseConnect, they will need to be specified in the data source or connection string.

It must contain all basic connection information plus any optional attributes. Because it uses the DRIVER= keyword, an odbcinst.ini file containing the driver location must exist (see "DSN-less connections").

The file data source is accessed by specifying the FILEDSN= instead of the DSN= keyword in a connection string, as outlined in the ODBC specification. The complete path to the file data source can be specified in the syntax that is normal for the machine on which the file is located. For example, on Windows:

FILEDSN=C:\Program Files\Common Files\ODBC\DataSources\Greenplum.dsn

or, on UNIX and Linux:

FILEDSN=/home/users/john/filedsn/Greenplum.dsn

If no path is specified for the file data source, the Driver Manager uses the DefaultDSNDir property, which is defined in the [ODBC File DSN] setting in the odbc.ini file to locate file data sources (see "Configuration through the system information (odbc.ini) file" for details). If the [ODBC File DSN] setting is not defined, the Driver Manager uses the InstallDir setting in the [ODBC] section of the odbc.ini file. The Driver Manager does not support the SQLReadFileDSN and SQLWriteFileDSN functions.

As with any connection string, you can specify attributes to override the default values in the data source:

FILEDSN=/home/users/john/filedsn/Greenplum.dsn;UID=john;PWD=test01