IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

Alternate Key from Multiple positions


IBM Mainframe Forums -> JCL & VSAM
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
sid_aec

New User


Joined: 01 Jul 2008
Posts: 60
Location: Kolkata

PostPosted: Fri Aug 03, 2012 12:19 am
Reply with quote

Hi,

If I want to build a alternate index for a VSAM where the Alternate Key would be from 2 to 10 bytes + then 16 to 10 bytes concatenated of Base VSAM.

Can you suggest how I need to define the alternate key parameter so that the alternate VSAM would have key as stated above + primary key of the base VSAM.Examples are typically starting and offset. Is there anyway I can acheive this.

Please help.
Back to top
View user's profile Send private message
Robert Sample

Global Moderator


Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA

PostPosted: Fri Aug 03, 2012 12:30 am
Reply with quote

Unload the VSAM file, move the data around so the alternate index key is contiguous and reload the VSAM file, then define your alternate index. As this quote from the Access Method Services for Catalogs manual indicates, you get one offset and one length to define your alternate index:
Quote:
KEYS(length offset| 64 0)
Describes the alternate-key field in the base cluster's data record.

The key field of an alternate index is called an alternate key. The data record's alternate key can overlap or be contained entirely within another (alternate or prime) key field.

The length plus offset cannot be greater than the length of the base cluster's data record.

When the base cluster's data record spans control intervals, the record's alternate-key field is within the record's first segment (that is, in the first control interval).

length offset
Gives the length of the alternate key, in bytes, and its displacement from the beginning of the base cluster's data record, in bytes.
If you cannot define your alternate key in one contiguous field on the record, then you cannot build the alternate index -- period. Either change the file layout or give up on the alternate index idea.
Back to top
View user's profile Send private message
Pete Wilson

Active Member


Joined: 31 Dec 2009
Posts: 580
Location: London

PostPosted: Wed Aug 08, 2012 5:42 pm
Reply with quote

You can have two separate alternate indices with each being keyed on different fields of the record, but you cannot concatenate two different parts of the record.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> JCL & VSAM

 


Similar Topics
Topic Forum Replies
No new posts INCLUDE OMIT COND for Multiple values... DFSORT/ICETOOL 5
No new posts Replace Multiple Field values to Othe... DFSORT/ICETOOL 12
No new posts Multiple table unload using INZUTILB DB2 2
No new posts Grouping by multiple headers DFSORT/ICETOOL 7
No new posts How to append a PS file into multiple... JCL & VSAM 3
Search our Forums:

Back to Top