Search notes:
SAS data set
A data set consists of data along with descriptor information.
A data set is identifyed by libref.filename. If libref is omitted, SAS chooses WORK as default.
Descriptor information
Information such as the
data types and length of variables (attributes) etc.
Two types of data sets
SAS knows two types of data sets: data files and data views.
Data files
Data files are organized with SAS libraries.
Data view
A data view stores the descriptor information and the observations in separate places.
Usually, a data view feels like a data file.
There are three types of data views:
- data step views
- SAS/ACCESS views
- PROC SQL views
proc dataset
Information about data sets can be read and changed with
proc datasets.
Indexes
Variables/attributes can be indexed on a data set. Indexes can then be used in
-
where statements in a data steps or proc steps.
-
by statements in data or proc steps.
-
key option on a set or modify statement.
Use idxname and idxwhere options to override default index usage.
options msglevel=i prints index usage into the log.
Check existence of a data set
The existence of a data set can be checked or verified with the
exist function.