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amitava
Warnings : 1
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Joined: 30 Oct 2005
Posts: 186
Location: India
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Hi Guys,
May be this question sound some weird! I am very new to IMS. I am writing some COBOL-IMS program in which I will call a IMS db to fetch some data depending upon some keys. May be I am not very much clear. Refer the example below -
IMS db Stucture -
Root : SHOP
Child : CUSTOMER
Child : PRODUCT.
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SHOP
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-------------------------------------------------------------------
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CUSTOMER PRODUCT
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SHOP is having the key field - product number - where child is a non-keyed segment.
Now in COBOL, I am making a GU call with the qualified SSA. Then I would like to know the CUSTOMER name by making a GNP call.
In this GNP call, is it required to use qualified/ unqualified SSA?
In a sentence, my question is - Is it necessary to include SSA (may be unqualified also) in GNP call where I have already made a GU call to the db? Please let me know the reason. I am waiting for it... |
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Sandy Zimmer
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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE
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| Why is CUSTOMER a child segment if there is only 1? |
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amitava
Warnings : 1
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Joined: 30 Oct 2005
Posts: 186
Location: India
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| Sandy, this is a kind of DB structure you can say! I cannot do with this. But I would like to about my query. Pls explain ... |
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Sandy Zimmer
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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE
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| Do you have the DBD? We need to see the SHOP and CUSTOMER definitions. In IMS, child dependent segments are defined as child segments because there can be 1 to many. Otherwise, the customer would be part of the root. |
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amitava
Warnings : 1
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Joined: 30 Oct 2005
Posts: 186
Location: India
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Sandy, I am sorry for the fact that I tried to use a hypothetical condition. And the example I have provided above is just an imagination. I even don't have any such db. But I would like to know about the qs -
If I am having an IMS db like -
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Root ----------- |---- Child1
| ---- Child2
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Then after making a GU call in root segment, if I want to make a GNP call in Child1, is it required to include the SSA of the Child1 segment? This is my basic question and the example I have put above, I used to make my doubt more clear. |
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Sandy Zimmer
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Posts: 826
Location: Wilmington, DE
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amitava
Warnings : 1
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Joined: 30 Oct 2005
Posts: 186
Location: India
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Sandy, probably u r getting me wrong -
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| This must be a class problem? First of all, take a look at this post (link below) and learn. I spent quite a bit of time on this and I think that it will help you. You do not need to do GNP - just read the post and then ask questions. And, from now on tell us if it is a "learning" problem. |
My question was - Is it madatory to include an SSA while making a GNP call? I faced this problem in my current project. I wrote a COBOL-IMS program where I initially hit the root segment with GU call along-with qualified SSA. After that I hit the child segment with GNP call without any SSA. Now my question is - will it work? May be it is working in my system because my IMS db structure is having 2 levels only (Root -> Child) and one to one relationship. But will it work if my db structure were having one to many relationship?
In my earlier post, I tried to put some example to make u all clear about my doubt! But alas! All those efforts were in vain-I was not able to make my question simpler rather made it little tough to understand. Sorry for that.
Waiting for your reply ... I think this time I have expressed my doubt/ question very clearly. |
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Srihari Gonugunta
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Joined: 14 Sep 2007
Posts: 295
Location: Singapore
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Amitava,
Take the following example
Hospital
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Ward
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Patient
Now, if you do a GU and located the hospital segment,
and then if you are doing a GNP without any SSA, you are retreiving all the Ward segments and Patinet segments under that hospital segment. If you do a GNP with Ward SSA, you will be getting only Wards not Patients under that hospital. and the same happens with Patient SSA.
It all depends on how you want to retrieve the segments. Hope my explanation helps. |
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Bitneuker
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Joined: 07 Nov 2005
Posts: 1104
Location: The Netherlands at Hole 19
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To get back to your original question:
no an SSA for GNP is optional. From the first link in one of my stickies and searching for GNP you might have found this
Have fun exploring IMS. |
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amitava
Warnings : 1
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Joined: 30 Oct 2005
Posts: 186
Location: India
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Srihari, thanks a lot! Now I have got it. But here again I have some questions -
Suppose the DB structure is -
Hospital
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Ward XXXXX
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Patient
Now my question is - If I issue a GNP call without any SSA attached with it after making a GU call in Hospital, which segment is supposed to be fetched and in which order? Will the oder be same as the segments are defined in the DBD libraries?
Please clear my doubts ... |
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Srihari Gonugunta
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Posts: 295
Location: Singapore
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| First it will go to Ward segment and fetches all the patient segments in this ward and then it goes to the next ward. It traverses like this till all the wards and patients are covered under the hospital segment. Please have a look at the traversing process in IMS. Please check the stickies provided by George for more information. |
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Sandy Zimmer
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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE
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| If you use SSAs down, then you do not need to set parentage. In my humble opinion, setting parentage is not necessary. It's more coding that is not needed unless you want ALL segment types under a particular parent. |
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Bitneuker
CICS Moderator
Joined: 07 Nov 2005
Posts: 1104
Location: The Netherlands at Hole 19
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| Srihari Gonugunta wrote: |
| Please check the stickies provided by George for more information. |
Thank you  I even did some work for him and posted this before:
no an SSA for GNP is optional. From the first link in one of my stickies and searching for GNP you might have found this |
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