330 Glossary
data value
in SAS, a unit of character or numeric information in a SAS data set. A data value
represents one variable in an observation.
database
an organized collection of related data. In most relational database management
systems, a database contains objects such as tables, views, and indices.
database management system (DBMS)
an integrated software package that enables you to create and manipulate data in
the form of databases. See also relational database management system.
DATA step view
a type of SAS data set that consists of a stored DATA step program. Like other SAS
data views, a DATA step view contains a definition of data that are stored elsewhere.
You create a DATA step view by specifying the VIEW= option in a DATA statement.
The view’s input data can come from one or more sources, including external files
and other SAS data sets. Because a DATA step view only reads (opens for input)
other files, you cannot update this view’s underlying data. DATA step views can
function only as input data sets.
editing data
the process of viewing a file with the ability to change its data. Depending on how
the file is accessed, observations may be viewed one at a time or as a group in a
tabular format.
engine
a part of SAS that reads from or writes to a file. Each engine supports access to files
of a particular format. There are several types of engines.
file
a collection of related records that are treated as a unit. SAS files are processed and
controlled through SAS and are stored in a SAS data library.
format
an instruction that SAS uses to display or write each value of a variable. Some
formats are supplied by SAS software. Other formats can be created by the user. In
SAS/ACCESS software, the default formats vary according to the interface product.
index
(1) in SAS software, a component of a SAS data set that enables SAS to access
observations in the data set quickly and efficiently. The purpose of SAS indices is to
optimize WHERE-clause processing and to facilitate BY-group processing. (2) in a
DMBS, a named object that directs the database management system (DBMS) to the
storage location of a particular data value for a given column. DBMS indices are also
used to optimize WHERE-clause processing and join processing.
Depending on how selection criteria are specified, SAS might use DBMS indices to
speed data retrieval.
informat
a pattern that SAS uses to determine how values that are entered in variable fields
should be interpreted. SAS provides a set of standard informats and also enables you
to define your own custom informats.
interface view engine
a SAS engine that retrieves data directly from files that have been formatted by
other software vendors.
libref
the name that is temporarily associated with a SAS data library. You assign a libref
with a LIBNAME statement or with operating system control language.
