Reading External Files

Reading raw data from various external sources is very important aspect of data processing.

With SAS it is very handy and flexible to read various types of data.

Reading Raw data files is done in 2 steps

A] Compilation

B] Execution

· When infile statement is encountered input buffer is created (Its default value is 256 bytes but can be changed using LRECL option) depending on one record size of the input file.

· When input statement is encountered then depending on number of variables PDV (Program Data Vector) is created into the memory.

· At the last descriptor portion of the output dataset is created

· These all 3 steps mentioned above take place at the compilation time.

Types of Input files

· Formatted input : Reding Raw data files using formatted Input

· Column input : Reding Raw data files using column Input

· List input : Reding Raw data files using list Input

· Named input : Reading Raw files with named Input

· Reading multiple external files at a time

· Reading Multiples records from one line - use of double trailing @

· Handling Mixed Record types; use of single trailing @

· Delimited Files: Reading Delimited Raw files

· Reading one Record scattered over multiple lines