environments. See the SAS documentation for your operating environment for more
information.
Sequential Data Libraries
SAS provides a number of features and procedures for reading from and writing to files
that are stored on sequential format devices, either disk or tape. Before you store SAS
libraries in sequential format, you should consider the following:
• You cannot use random access methods with sequential SAS data sets.
• You can access only one of the SAS files in a sequential library, or only one of the
SAS files on a tape, at any point in a SAS job.
For example, you cannot read two or more SAS data sets in the same library or on
the same tape at the same time in a single DATA step. However, you can access:
• two or more SAS files in different sequential libraries, or on different tapes at the
same time, if there are enough tape drives available
• a SAS file during one DATA or PROC step, and then access another SAS file in
the same sequential library or on the same tape during a later DATA or PROC
step
Also, when you have more than one SAS data set on a tape or in a sequential library
in the same DATA or PROC step, one SAS data set file might be opened during the
compilation phase. The additional SAS data sets are opened during the execution
phase. For more information, see the “SET Statement” in SAS Statements: Reference.
• For some operating environments, you can read from or write to SAS data sets only
during a DATA or PROC step. However, you can always use the COPY procedure to
transfer all members of a SAS library to tape for storage and backup purposes.
• Considerations specific to your site can affect your use of tape. For example, it might
be necessary to manually mount a tape before the SAS libraries become available.
Consult your operations staff if you are not familiar with using tape storage at your
location.
For information about sequential engines, see Chapter 35, “SAS Engines,” on page
739.
Operating Environment Information
The details for storing and accessing SAS files in sequential format vary with the
operating environment. See the SAS documentation for your operating environment
for more information.
Tools for Managing Libraries
SAS Utilities
The SAS utilities that are available for SAS file management enable you to work with
more than one SAS file at a time, as long as the files belong to the same library. The
advantage of learning and using SAS Explorer, functions, options, and procedures is that
they automatically copy, rename, or delete any index files or integrity constraints, audit
586 Chapter 24 • SAS Libraries
trails, backups, and generation data sets that are associated with your SAS data files.
Another advantage is that SAS utility procedures work on any operating environment at
any level.
There are several SAS window options, functions, and procedures available for
performing file management tasks. You can use the following features alone or in
combination, depending on what works best for you. See “Choosing the Right
Procedure” in Base SAS Procedures Guide for detailed information about SAS utility
procedures. The SAS windowing environment and how to use it for managing SAS files
is discussed in Chapter 16, “Introduction to the SAS Windowing Environment,” on page
355 and Chapter 17, “Managing Your Data in the SAS Windowing Environment,” on
page 375 as well as in the online Help.
CATALOG procedure
provides catalog management utilities with the COPY, CONTENTS, and APPEND
procedures.
DATASETS procedure
provides all library management functions for all member types except catalogs. If
your site does not use the SAS Explorer, or if SAS executes in batch or interactive
line mode, using this procedure can save you time and resources.
SAS Explorer
includes windows that enable you to perform most file management tasks without
submitting SAS program statements. Type LIBNAME, CATALOG, or DIR in the
Toolbar window to use SAS Explorer, or select the Explorer icon from the Toolbar
menu.
DETAILS system option
Sets the default display for file information when using the CONTENTS or
DATASETS procedure. When enabled, DETAILS provides additional information
about files, depending on which procedure or window you use.
Library Directories
SAS Explorer and SAS procedures enable you to obtain a list, or directory, of the
members in a SAS library. Each directory contains the name of each member and its
member type. For the member type DATA, the directory indicates whether an index,
audit trail, backup, or generation data set is associated with the data set. The directory
also describes some attributes of the library, but the amount and nature of this
information vary with the operating environment.
Note: SAS libraries can also contain various SAS utility files. These files are not listed
in the library directory and are for internal processing.
Accessing Permanent SAS Files without a Libref
SAS provides another method of accessing files in addition to assigning a libref with the
LIBNAME statement or using the New Library window. To use this method, enclose the
filename, or the filename and the SAS library, in single quotation marks.
For example, in a directory-based system, if you want to create a data set named MyData
in your default directory, that is, in the directory that you are running SAS in, you can
write the following line of code:
data 'mydata';
SAS creates the data set and remembers its location for the duration of the SAS session.
Tools for Managing Libraries 587
If you omit the single quotation marks, SAS creates the data set MyData in the
temporary Work subdirectory, named Work.MyData:
data mydata;
If you want to create a data set named MyData in a library other than the directory in
which you are running SAS, enclose the entire pathname in quotation marks, following
the naming conventions of your operating environment. For example, the following
DATA step creates a data set named Foo in the directory C:sasrunmydata
data 'c:sasrunmydatafoo';
This method of accessing files works on all operating environments and in most contexts
where a libref.data-set-name is accepted as a SAS data set. Most data set options can be
specified with a quoted name.
You cannot use quoted names for the following:
• SAS catalogs
• MDDB and FDB references
• contexts that do not accept a libref, such as the SELECT statement of PROC COPY
and most PROC DATASETS statements
• PROC SQL
• DATA step stored programs, or SAS views
• SAS Component Language (SCL) open function
The following table shows some examples of DATA statements that access SAS data
files without using a libref.
Table 24.2 Example DATA Statements That Access SAS Files without Using a Libref
Operating
Environment Examples
DOS, Windows
data 'c:
ootmystuffsasstuffworkmyfile';
UNIX
data '/u/root/mystuff/sastuff/work/myfile';
z/OS
data 'user489.mystuff.saslib(member1)';
/* bound SAS library */
data '/mystuff/sasstuff/work/myfile';
/* UNIX file system library */
Operating Environment Commands
You can use operating environment commands to copy, rename, and delete the operating
environment file or files that make up a SAS library. However, to maintain the integrity
of your files, you must know how the SAS library model is implemented in your
operating environment. For example, in some operating environments, SAS data sets and
their associated indexes can be copied, deleted, or renamed as separate files. If you
rename the file that contains the SAS data set, but not its index, the data set is marked as
damaged.
CAUTION:
588 Chapter 24 • SAS Libraries
Using operating environment commands can damage files. You can avoid
problems by always using SAS utilities to manage SAS files.
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590 Chapter 24 • SAS Libraries
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