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srinis Warnings : 1 New User
Joined: 04 Jun 2007 Posts: 5 Location: chennai
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Hi,
i am not working on Ims db, but i know. i want a little bit explanation of Secondary Index concept.
Regards,
sree. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006 Posts: 19244 Location: Inside the Matrix
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Hello,
A secondary index in IMS (as well as vsam, db2, and any other database) provides additonal direct access to rows.
For example an "employee" table might have a primary key of "employee_id". Each employee also has their current department code in their employee table entry. If dept_no was a secondary index, a query could directly retrieve all of the people in a specific department without traversing the entire table. |
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Bitneuker
CICS Moderator
Joined: 07 Nov 2005 Posts: 1104 Location: The Netherlands at Hole 19
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I wonder why I posted the sticky telling people where to find information about IMS Again: following the first link in this sticky and searching for 'SECONDARY INDEX' i.e. leads to this, and there's a lot more to find. |
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Devzee
Active Member
Joined: 20 Jan 2007 Posts: 684 Location: Hollywood
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srinis Refer to
post which has generic concept of secondary indexing.
Bitneuker Not everyone looks at the sticky or the links. People need direct answers without spending much time in reading the manuals or understanding the full concept. |
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Bitneuker
CICS Moderator
Joined: 07 Nov 2005 Posts: 1104 Location: The Netherlands at Hole 19
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Quote: |
Bitneuker Not everyone looks at the sticky or the links. People need direct answers without spending much time in reading the manuals or understanding the full concept. |
Devzee: They should IMHO. The original question posted tells us the guy wants to understand S.I. He didn't post a direct question to solve any problem so in this case I think leading him to the information via links is a good option. Please take my original post as 'non posted'. |
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autobox
New User
Joined: 19 Aug 2005 Posts: 51
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Simplly put, Secondary Index is that you can use a key other than the original key of root segment to access a certain segment occurence directly. |
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Sandy Zimmer
Active Member
Joined: 13 Jun 2007 Posts: 826 Location: Wilmington, DE
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Using an IMS utility to build secondary indices as individual databases is fast. You then read the secondary index as a database. Talk to your DBA. I wrote an HR system with 5 secondary indices. It worked great! |
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