Read IMS DB from Start to End.

Archana_MF · Posted: Tue Oct 30, 2007 10:40 pm

Hi All,

I need to write a routine to Read the IMS DB from Start till End, from the very first Record to the Last.

Can I use GN & GNP for this process? but how do I position the pointer at first record without giving the Key?

I have worked on DB2/Datacom but on IMS DB/DC this is the first Project.

Please Advice.
Thank You All.

Sandy Zimmer · Posted: Wed Oct 31, 2007 2:55 am

To begin - do a GU with no SSAs. Then do a GN with no SSAs - you will get every segment - parent - children - grandchildren - etc-etc. After each call, check for GB - end of database. You can determine which segment type you are on by looking at the key feedback area in your PCB - look at segment level also.

Devzee · Posted: Wed Oct 31, 2007 9:01 am

Sandy Zimmer · Posted: Wed Oct 31, 2007 4:42 pm

A GU with no SSAs will always position you at the beginning of the database.

Srihari Gonugunta · Posted: Wed Oct 31, 2007 6:52 pm

Even a direct GN call without SSAs will position at the beginning of the DB.

publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=/com.ibm.ims9.doc.apdb/p3hgnp.htm

First GN or GU
and in the loop GN will serve the requirement, I suppose. Please correct me if I am wrong.

Bitneuker · Posted: Wed Oct 31, 2007 7:04 pm

I think there's no need to discuss the positioning at the first segment of the database. TS got the answer how to access all segments.

Archana_MF · Posted: Wed Oct 31, 2007 10:32 pm

Thank you all.

Just one more Question.

GU followed with GN and do I need to use GNP after GN to get the Child Segments or will GN bring all?.

I programmed it as
GU with unqualified SSA follwed with GN within which GNP will be looped until 'GE' status. & The GN loop is checked for 'GB' status.
Yet to run the job, facing some PSB issues.

Thank you once again.
Archana

Sandy Zimmer · Posted: Wed Oct 31, 2007 10:37 pm

Absolutely NO SSa's. Just read with your GN and PCB and a work area large enough for all segment types. Once you have spaces in your status code - check for that before your GB - check the segment level in your PCB to determine what segment you have. You can also look at the key feedback area to see any key values - including parent segments.

What's up with the PSB? What is the purpose of this program?

Archana_MF · Posted: Wed Oct 31, 2007 10:40 pm

I am running it as a Batch Job as I need to write each segment to a output file in specific format.
I was getting U0476 Abend but just fixed it.

Thank You!

Sandy Zimmer · Posted: Wed Oct 31, 2007 10:42 pm

OK - when you know what segment type you have, you can move it from your "global read area" into the specific ws area and write from there. Is it variable length?

Bitneuker · Posted: Wed Oct 31, 2007 11:43 pm

Sandy wrote:

Sandy Zimmer · Posted: Wed Oct 31, 2007 11:53 pm

Yes, George!

GA
call completed successfully but higher level crossed for GN or GNP call
GB
end of database reached on GN call
GK
call completed successfully but different segment type on same level retrieved for GN

Sandy Zimmer · Posted: Wed Oct 31, 2007 11:58 pm

GK will not happen if you leave off the SSAs.....IMS reads left to right up and down

Bitneuker · Posted: Thu Nov 01, 2007 3:51 am

Sandy Zimmer wrote:

Sandy Zimmer · Posted: Thu Nov 01, 2007 4:05 am

Mostly, George - sometimes it just needs a little boost! Always remember - age is JUST a number!

Bitneuker · Posted: Thu Nov 01, 2007 4:11 am

Yep it is

Don't think I'm not at the forum whenever I don't post. I look at the reactions and as long as it's all right I don't interfere. But when it's not all right I don't hesitate and react

Archana_MF · Posted: Fri Nov 02, 2007 4:27 am

Hi,

The GU with Unqualified SSA gave me AJ status.
So I directly gave GN with no SSA as suggested by Sandy Zimmer and it worked.

George,
First I didn't understand what you were saying about the hierarchy but after my program returned the GA status I understood.

Thank you ALL Guys.
GREAT HELP!!!

Sandy Zimmer · Posted: Fri Nov 02, 2007 4:53 am

Archana,

I am so happy that this worked for you! A GU will work only if you use NO ssa's....No qualifed - No unqualified - NO ssa.....

AJ
SSA specified for the call is invalid

One more point I want to make - if you do not check for GB - with no SSAs - you will just keep going - you will start again at the beginning of the database - you will be the enigizer bunny!

Bitneuker · Posted: Fri Nov 02, 2007 3:41 pm

Hi Archana,

Please read the answers you get carefully

. In a previous post Sandy wrote:

Archana_MF · Posted: Fri Nov 02, 2007 9:50 pm

George,
The GU with SSA did not work but the GN with No SSA Worked.

Thank You!

Bitneuker · Posted: Fri Nov 02, 2007 10:41 pm

Sandy wrote no SSA's at all so also the GU should be done without any SSA.

donateeye · New User Joined: 01 Jun 2007 Posts: 62 Location: chennai

please give me a link to download IMS DB learning material

Bitneuker · Posted: Tue Nov 27, 2007 10:30 pm