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How can one differentiate between a flat file and a VSAM

 
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bh

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Joined: 19 Mar 2006
Posts: 26
Location: India

PostPosted: Thu May 24, 2007 4:58 pm    Post subject: How can one differentiate between a flat file and a VSAM
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Hi,

How can one differentiate between a flat file and a VSAM file being used in a COBOL program ?


Regards,
gp
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William Thompson

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Joined: 18 Nov 2006
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Location: Tucson AZ

PostPosted: Thu May 24, 2007 6:08 pm    Post subject:
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Isn't a different SELECT specification required?
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pingte

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PostPosted: Thu May 31, 2007 2:04 pm    Post subject:
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VSAM will have 2 components- data and index. This will be 2 separate files associated with the main file.
Flat file has no such components.
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expat

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Joined: 14 Mar 2007
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PostPosted: Thu May 31, 2007 2:45 pm    Post subject:
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Quote:
VSAM will have 2 components- data and index.

Where is the index component of an ESDS / RRDS ?
Also an ESDS can have an associated AIX and PATH !
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pingte

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PostPosted: Thu May 31, 2007 2:57 pm    Post subject:
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KSDS will have data and index component..

Also AIX and PATH are for Alternate Cluster. It can be there for KSDS.
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donevin

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PostPosted: Thu May 31, 2007 4:37 pm    Post subject:
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As William said a different slect statement is required. For flat files access mode and organization must be sequential. For relative record files, organization is relative, access mode can be sequential, random or dynamic and the same goes for key-sequential files where access mode is concerned. For key-sequential files organization is indexed and a record key must be declared. For RR files a relative key must be declared. This is off of the top of my head but should make the differences in the select statement clearer.
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