SAS 9.4 Language Reference, 6th Edition

SAS view

is a virtual data set that points to data from other sources. SAS views have a member

type of VIEW. For specific information, see Chapter 29, “SAS Views,” on page

675.

Note: The term SAS data set is used when a SAS view and a SAS data file can be used

in the same manner.

Descriptor Information for a SAS Data Set

The descriptor information for a SAS data set makes the file self-documenting. That is,

each data set can supply the attributes of the data set and of its variables. Once the data is

in the form of a SAS data set, you do not have to specify the attributes of the data set or

the variables in your program statements. SAS obtains the information directly from the

data set.

Descriptor information includes the number of observations, the observation length, the

date that the data set was last modified, and other facts. Descriptor information for

individual variables includes attributes such as name, type, length, format, label, and

whether the variable is indexed.

The following figure illustrates the logical components of a SAS data set:

602 Chapter 27 • SAS Data Sets

Figure 27.1 Logical Components of a SAS Data Set

The following items correspond to the numbers in the figure above:

1. A SAS view (member type VIEW) contains descriptor information and uses data

values from one or more data sets.

2. A SAS data file (member type DATA) contains descriptor information and data

values. SAS data sets can be a member type DATA (SAS data file) or VIEW (SAS

view).

3. An index is a separate file that you can create for a SAS data file in order to provide

direct access to specific observations. The index file has the same name as its data

file and a member type of INDEX. Indexes can provide faster access to specific

observations, particularly when you have a large data set.

4. Extended attributes are metadata that is defined on a data set or on a variable

(column). Extended attributes are represented as name-value pairs and are created

using the DATASETS procedure.

Descriptor Information for a SAS Data Set 603