Specifying File Names in the OLAP DML

Using the fileunit

The FILEOPEN function opens a file and returns an integer that uniquely identifies that file. This identifier is known as a fileunit. Once you have opened a file and obtained a fileunit, all subsequent calls to data-reading commands and file I/O commands for that file reference the fileunit instead of the file name.

Using file identifiers

A file identifier is a character string that specifies a file stored on disk. The file identifier always includes the file name. In addition, other information might be required to specify the full path location of the file. The format of file identifiers is different on different operating systems.

In the Windows environment, the format in which you specify a file name depends on where the file is located:

• For files that are local to the computer on which OLAP Services is running, use DOS format.

• For files remote to the computer on which OLAP Services is running, use either DOS or UNC format, unless explicitly stated otherwise in the documentation. However, be consistent; all references to a given file must be in the same format.

Syntax: DOS file name format

DOS file name format is as follows.

 [d:] [\][path\] filename[.ext]

The d argument designates a disk drive.

The path argument is a path of directory names separated by backslash (\) characters.

The filename argument is the name of the file.

The ext argument is a 1- to 3-character extension preceded by a period.

Syntax: UNC file name format

UNC file name format is as follows

\\host\share\[path\] filename[.ext]

The host argument designates the host system.

The share keyword designates a shared area on the host.

The path argument is a path of directory names separated by backslash (\) characters.

The filename argument is the name of the file.

The ext argument is a 1- to 3-character extension preceded by a period.

Specifying a file identifier as a text expression

When specifying file identifiers in OLAP DML commands, it is good practice to always enclose them in single quotation marks. This will prevent parsing errors in cases where file name components are also OLAP DML object names or reserved words.

The backslash character (\) in file identifiers is of special importance. The backslash is interpreted as an escape character. Therefore, when specifying a file identifier as a text expression, you must use double backslashes to designate single backslashes.

In most cases, when parsing file names:

• Forward slashes are converted to backslashes. This feature allows you to specify one forward slash instead of two backslashes.

• Extra backslash characters are removed when they occur anywhere in a path name other than in the first two column positions.