Often the first step in setting up your SAS session is to define the libraries. You can use programming statements to assign library names.

To reference a permanent SAS file:

A logical name (libref) can be assigned to a SAS library using the LIBNAME statement. You can include the LIBNAME statement with any SAS program so that the SAS library is assigned each time the program is submitted. Using the user interface, you can set up LIBNAME statements to be automatically assigned when SAS starts.

The LIBNAME statement below assigns the libref Cert to the SAS library C:UsersStudent1Cert in the Windows environment. When the default engine is used, you do not have to specify it in the LIBNAME statement.

libname cert 'C:UsersStudent1Cert';

The table below gives examples of physical names for SAS libraries in various operating environments.

After assigning a libref, it is a good idea to check the log to verify that the libref has been assigned successfully.

1    libname cert 'C:UsersStudent1Cert';
NOTE: Libref CERT was successfully assigned as follows:
      Engine:        V9
      Physical Name: C:UsersStudent1Cert

The LIBNAME statement is global, which means that the librefs remain in effect until changed or canceled, or until the SAS session ends.

By default, the LIBNAME statement assigns the libref for the current SAS session only. Each time you begin a SAS session, you must assign a libref to each permanent SAS library that contains files that you want to access in that session. (Remember that Work is the default libref for a temporary SAS library.)

After you assign a libref, you specify it as the first element in the two-level name for a SAS file.

In order for the PRINT procedure to read cert.admit, you specify the two-level name of the file as follows:

proc print data=cert.admit; 
run;

You can use the LIBNAME statement to reference not only SAS files but also files that were created with other software products, such as database management systems.

A SAS engine is a set of internal instructions that SAS uses for writing to and reading from files in a SAS library or a third-party database. SAS can read or write these files by using the appropriate engine for that file type. For some file types, you need to tell SAS which engine to use. For others, SAS automatically chooses the appropriate engine.

An example of an engine that accesses third-party data is the XLSX engine, which processes Microsoft Excel workbooks.

If your site licenses SAS/ACCESS software, you can use the LIBNAME statement to access data that is stored in a database management system (DBMS) file. The types of data you can access depend on your operating environment and on which SAS/ACCESS products you have licensed. For more information about SAS/ACCESS engines, see the SAS documentation for your DBMS.