SAS/ACCESS Descriptor Files

Defining SAS/ACCESS Descriptor Files

SAS/ACCESS descriptor files are the tools that SAS/ACCESS uses to establish a connection between SAS and SYSTEM 2000. You use the ACCESS procedure to create the two types of descriptor files: access (member type ACCESS) and view (member type VIEW).

An access descriptor contains information about the SYSTEM 2000 database that you want to use. The information includes the database name, the item names, and their item types. An access descriptor also contains SAS information, such as the SAS variable names, formats, and informats. Think of an access descriptor as being a master descriptor file for one SYSTEM 2000 database because it contains a complete description of that database. You cannot create a single access descriptor that references two SYSTEM 2000 databases. An access descriptor is used to create view descriptors.

A view descriptor defines all the data or a subset of the data described by one access descriptor. View descriptor files are sometimes called SAS views. This documentation uses view descriptor for these files to distinguish them from views created by the SQL procedure.

You choose a subset of data by selecting specific items and specifying selection criteria that the data must meet. For example, you might select the two items LAST NAME and CITY-STATE, and specify that the value stored in item CITY-STATE must be AUSTIN TX, or your selection criteria might be the date of transaction and customers' names that begin with W. After you create your view descriptor, you can use it in a SAS program to read data directly from the SYSTEM 2000 database or to extract the data and place it in a SAS data file. You can also specify a sequence order for the data.

For each access descriptor that you define, you usually have several view descriptors. Each of these view descriptors contains different subsets of data.

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