Difference between Dummy & Temporary datasets

rambabu · Active User Joined: 18 Apr 2005 Posts: 67

What is the difference between dummy and temporary datasets? Can we pass the temporary dataset to another step?

priya · Posted: Fri Apr 22, 2005 11:56 am Post subject:

Dummy dataset doesn't occupy memory, while Temporary dataset occupies memory. (they are created and deleted within the job scope)

Yes, You can pass Temporary datasets to another steps.

mmwife · Super Moderator Joined: 30 May 2003 Posts: 1504

When a dummy I/P ds is read an immediate EOF occurs.
When a dummy O/P ds is written to, no data is transferred.

If you concatenate dummy ds in other than the last position in the concat, the 1st read of the dummy ds produces an EOF, even if there are real ds following in the concat.

andycool · Active User Joined: 12 Apr 2005 Posts: 65

Can anyone let me know the use of a dummy dataset.
Please explain creating some situation.

Regards,

vijayamadhuri · Active User Joined: 06 Apr 2005 Posts: 187

The dummy dataset is coded on the DD ststement to test the execution of the pgm without actually reading or writing into the dataset.It basically
simulates the presence of the file even without it actually existing.

//ddname DD DUMMY
or
DD DSN=nullfile

if the DUMMY FILE IS READ the O.S sends an EOF indicator to the pgm being executed.This will result the pgm to execute based on it's logic without actually reading any data.
If write is requested the file being imaginary is simply ignored.