About External Files

An external file, sometimes called a flat file or a raw data file, is a plain text file that often contains one record per line. Within each record, the fields can have a fixed length or they can be separated by delimiters, such as commas. Like SAS or DBMS tables, external files can be used as inputs and outputs in SAS Data Integration Studio jobs. Unlike SAS or DBMS tables, which are accessed with SAS LIBNAME engines, external files are accessed with SAS INFILE and FILE statements. Accordingly, external files have their own registration wizards, and they have two special transformations in the Transformations tree: File Reader and File Writer.

The most common tasks for external files are listed in the following table.

Common External File Tasks
Task	Action
Register an external file (add metadata about the file's physical location, columns, and other attributes).	For more information, see Registering a Delimited External File, Registering a Fixed-Width External File , and Registering an External File with User-Written Code.
Specify a registered external file as a source or a target in a job.	For more information, see Using an External File in the Process Flow for a Job.
View the data or metadata for a registered external file.	For more information, see Viewing Data in External Files and Viewing or Updating External File Metadata.