File Data Sources

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, either Windows, UNIX, or Linux. See “Quick Start Connect” for a general description of ODBC data sources on both Windows and UNIX.

A file data source is simply a text file that contains connection information. It can be created through the Linux ODBC Administrator (see “Configuration Through the Administrator”) or it can be created with a text editor. The file normally has an extension of .dsn.

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

[ODBC]

Driver=DataDirect Oracle Wire Protocol

Port=1522

HostName=ORA2

LogonID=JOHN

Servicename=SALES.US.ACME.COM

CatalogOptions=1

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\Oraclewp.dsn

or, on UNIX and Linux:

FILEDSN=/home/users/john/filedsn/Oraclewp2.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/Oraclewp2.dsn;UID=james;PWD=test01