SAS Certification Prep Guide: Base Programming for SAS 9, Third Edition

How SAS Processes Programs

When you submit a DATA step, SAS processes the DATA step and then creates a new SAS data set. Let's see exactly how that happens.

A SAS DATA step is processed in two phases:

• During the compilation phase, each statement is scanned for syntax errors. Most syntax errors prevent further processing of the DATA step. When the compilation phase is complete, the descriptor portion of the new data set is created.
• If the DATA step compiles successfully, then the execution phase begins. During the execution phase, the DATA step reads and processes the input data. The DATA step executes once for each record in the ...