Portal | IBM Manuals | Downloads | Products | Refer | Info | Programs | JCLs | Forum Rules*| Site Map | Mainframe CD 
IBMMAINFRAMES.com - IBM Mainframe Support Forums Index
 
Register
 
IBMMAINFRAMES.com - IBM Mainframe Support Forums Index FAQ Search Memberlist Usergroups Profile Log in to check your private messages Log in
 
How the VSAM KSDS uses index to locate the records ???

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> SMS & VSAM
Author Message
Thirumurgann

New User


Joined: 13 Feb 2008
Posts: 9
Location: Chennai

PostPosted: Fri Jul 25, 2008 4:53 pm    Post subject: How the VSAM KSDS uses index to locate the records ???
Reply with quote

If your answer is primary key then tell me how it get mapped to index of the particular record. Much confused about index whether its a memory pointer??? please help me to understand this concept clear with some Examples....
Back to top
View user's profile Send private message
References
Robert Sample

Senior Member


Joined: 06 Jun 2008
Posts: 891
Location: Atlanta, GA

PostPosted: Fri Jul 25, 2008 5:01 pm    Post subject:
Reply with quote

There is an IBM Redbook entitled "VSAM Demystified", http://www.redbooks.ibm.com/abstracts/sg246105.html?Open which will provide you with 508 pages of information on how VSAM works, exactly.
Back to top
View user's profile Send private message
expat

Global Moderator


Joined: 14 Mar 2007
Posts: 3509
Location: Brussels once more ...

PostPosted: Fri Jul 25, 2008 5:03 pm    Post subject:
Reply with quote

A good intro to VSAM
Back to top
View user's profile Send private message
Thirumurgann

New User


Joined: 13 Feb 2008
Posts: 9
Location: Chennai

PostPosted: Fri Jul 25, 2008 5:21 pm    Post subject: Thanks Robert for reffering such wonderful book
Reply with quote

icon_lol.gif
Back to top
View user's profile Send private message
dick scherrer

Global Moderator


Joined: 23 Nov 2006
Posts: 8643
Location: 221 B Baker St

PostPosted: Fri Jul 25, 2008 9:03 pm    Post subject:
Reply with quote

Hello,

A somewhat less technical way to think of this is to think of the index of a vsam file like the index of an IBM manual. The index of the manual is concise containing the "key"s and a reference to the page in the manual containing the information.

The index of a vsam file works in much the same way. VSAM locates the key value in the index and from there gets the reference pointer to the actual data.

The actual data is then read and returned to the program like when we go to the indexed page and read what is there.
Back to top
View user's profile Send private message
Thirumurgann

New User


Joined: 13 Feb 2008
Posts: 9
Location: Chennai

PostPosted: Mon Jul 28, 2008 12:18 pm    Post subject: Clear explanation Thanks dick scherrer
Reply with quote

icon_biggrin.gif
Back to top
View user's profile Send private message
Thirumurgann

New User


Joined: 13 Feb 2008
Posts: 9
Location: Chennai

PostPosted: Mon Aug 04, 2008 11:56 am    Post subject:
Reply with quote

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

Global Moderator


Joined: 23 Nov 2006
Posts: 8643
Location: 221 B Baker St

PostPosted: Mon Aug 04, 2008 12:07 pm    Post subject: Reply to: How the VSAM KSDS uses index to locate the records
Reply with quote

You're welcome icon_smile.gif

d
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> SMS & VSAM All times are GMT + 6 Hours
Page 1 of 1