SAS 9.4 Language Reference, 6th Edition

• When a SAS file is opened for output, it is created in the first library that is listed in

the concatenation.

• When you delete or rename a SAS file, only the first occurrence of the file is

affected.

• Any time a list of SAS files is displayed, only one occurrence of a filename is

shown, even if the name occurs multiple times in the concatenation. For example, if

library One contains A.DATA and library Two contains A.DATA, only A.DATA

from library One is listed because it is the first occurrence of the filename.

In addition, a SAS file that is logically connected to another file (such as an index to

a data file) is listed only if the parent file is the first (or only) occurrence of the

filename. For example, if library One contains A.DATA and library Two contains

A.DATA and A.INDEX, only A.DATA from library One is listed. A.DATA and

A.INDEX from library Two are not listed.

• If any library in the concatenation is sequential, then the concatenated library is

considered sequential by applications that require random access. For example, the

DATASETS procedure cannot process sequential libraries, and therefore cannot

process a concatenated library that contains one or more sequential libraries.

• The attributes of the first library that is specified determine the attributes of the

concatenation. For example, if the first SAS library that is listed is “read only,” then

the entire concatenated library is “read only.”

• Once a libref has been assigned in a concatenation, any changes made to the libref

does not affect the concatenation.

• Changing a data set name to an existing name in the concatenation will fail.

Permanent and Temporary Libraries

SAS libraries are generally stored as permanent data libraries. However, SAS provides a

temporary or scratch library where you can store files for the duration of a SAS session

or job.

A permanent SAS library is one that resides on the external storage medium of your

computer and is not deleted when the SAS session terminates. Permanent SAS libraries

are stored until you delete them. The library is available for processing in subsequent

SAS sessions. When working with files in a permanent SAS library, you generally

specify a libref as the first part of a two-level SAS filename. The libref tells SAS where

to find or store the file.

Note: You can also skip using a libref and point directly to the file that you want to use,

using syntax that your operating system understands. An example of this in the

Windows environment is

data 'C:\root\sasfiles\myfile.ext';

Operating Environment Information

Files are specified differently in various operating environments. See the SAS

documentation for your operating environment for more information.

A temporary SAS library is one that exists only for the current SAS session or job. SAS

files that are created during the session or job are held in a special work space that might

or might not be an external storage medium. This work space is generally assigned the

default libref Work. Files in the temporary Work library can be used in any DATA step

or SAS procedure during the SAS session, but they are typically not available for

592 Chapter 26 • SAS Libraries