Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
Can we specify a key in a GSAM file

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
Verma,Raman

New User


Joined: 13 Oct 2006
Posts: 15

PostPosted: Fri Feb 16, 2007 2:58 pm    Post subject: Can we specify a key in a GSAM file
Reply with quote

Hi ,

Can we have a key in a GSAM file.

I have to read a large volume of data into a GSAM file in a program that employs check pointing. I want to access this data in a random fashion in the subsequent steps.
Can a GSAM file have a key and can we access it with a GU call using the key?

The problem why I am not trying out VSAM is that I donot want to repeat the copy process in case I get an abend.

Thanks...
Raman
Back to top
View user's profile Send private message

dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Sat Feb 17, 2007 2:43 am    Post subject:
Reply with quote

Hello,

If the dsorg for your GSAM file is PS, you cannot. Physical Sequential files have no keying mechanism.

I'd use VSAM for the random processing requirement and you can define as many keys as you need to support the processes that run after the first completes.
Back to top
View user's profile Send private message
superk

Moderator Team Head


Joined: 26 Apr 2004
Posts: 4650
Location: Raleigh, NC, USA

PostPosted: Sat Feb 17, 2007 2:49 am    Post subject: Re: Can we specify a key in a GSAM file
Reply with quote

I found these bullet items in the document Application Programming: Database Manager:


  • An IMS program can retrieve records and add records to the end of the GSAM database, but the program cannot delete or replace records in the database.
  • You use separate calls to access GSAM databases. (Additional checkpoint and restart considerations are involved in using GSAM.)
  • Your program must use symbolic CHKP and XRST calls if it uses GSAM. Basic CHKP calls cannot checkpoint GSAM databases.
  • When an IMS program uses a GSAM data set, the program treats it like a sequential nonhierarchic database. The MVS access methods that GSAM can use are BSAM on direct access, unit record, and tape devices; and VSAM on direct-access storage. VSAM data sets must be nonkeyed, non indexed, entry-sequenced data sets (ESDS) and must reside on DASD. VSAM does not support temporary, SYSIN, SYSOUT, and unit-record files.
  • Because GSAM is a sequential nonhierarchic database, it has no segments, no keys, and no parentage.
Back to top
View user's profile Send private message
Verma,Raman

New User


Joined: 13 Oct 2006
Posts: 15

PostPosted: Mon Feb 19, 2007 10:39 am    Post subject: Re: Can we specify a key in a GSAM file
Reply with quote

Hi Superk and Dick Scherrer,

Your guidance was really helpful.I have been able to find a lateral path to my problem because of the timely help.

Thanks...
Raman
Back to top
View user's profile Send private message
dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Tue Feb 20, 2007 1:20 am    Post subject:
Reply with quote

You're welcome.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts Compare yesterday's date to the one o... migusd SYNCSORT 8 Fri Sep 22, 2017 11:35 pm
No new posts Split 1 file into 10 output Files - S... Prasanth Kumar SYNCSORT 5 Sat Sep 16, 2017 12:02 am
No new posts BUILD OUTFIL based on condition other... balaji81_k DFSORT/ICETOOL 13 Fri Sep 08, 2017 11:06 pm
No new posts Skip file from delete pema_yozer All Other Mainframe Topics 3 Tue Aug 29, 2017 3:19 pm
No new posts editting the file by inserting zeros ... pramodrsingh DFSORT/ICETOOL 9 Mon Aug 21, 2017 5:58 pm

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us