SAS interacts
with
CA-Datacom/DB through
an interface view engine that uses
SAS/ACCESS descriptor files created
with the ACCESS procedure. There are two types of descriptor files:
-
access descriptor files (member
type ACCESS)
-
view descriptor files (member type
VIEW)
An access descriptor
contains information about the
CA-Datacom/DB table that you want to use. The information includes
the table name, the field names, and their data types. You use the
access descriptor to create view descriptors. Think of an access
descriptor as a master descriptor file for a single
CA-Datacom/DB table, because it usually contains
a complete description of that table.
A view descriptor defines
a subset of the data described by an access descriptor. You choose
this subset by selecting particular fields in the
CA-Datacom/DB table, and you can specify selection
criteria that the data must meet. For example, you might want to
select two fields, LAST-NAME and CITY-STATE, and specify that the
value stored in field CITY-STATE must be
AUSTIN TX. You can also specify a sequence order for the data. After you
create your view descriptor, you can use it in a SAS program to read
data directly from the
CA-Datacom/DB table or to extract the data and place it in a SAS data file.
Typically, for each access descriptor that you define, you have several
view descriptors, each selecting different subsets of data.