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Why 2 Databases(DB2 and Vsam) in a single application?

 
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haidude

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Joined: 11 May 2007
Posts: 10
Location: Mumbai

PostPosted: Tue Jun 12, 2007 10:16 am    Post subject: Why 2 Databases(DB2 and Vsam) in a single application?
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I have faced one interview in this below question.Why 2 databases in a single application(DB2 and Vsam),why not one database(either DB2 or Vsam)?
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ofer71

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Joined: 27 Dec 2005
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PostPosted: Tue Jun 12, 2007 10:37 am    Post subject:
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VSAM is not a database; It is an Access Method.

Do you know that DB2 keeps its data in VSAM files?

O.
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haidude

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PostPosted: Tue Jun 12, 2007 1:30 pm    Post subject:
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I am agree with ur post but my question is why most of the Mainfrae application contain Db2 and Vsam,is there any specific reason?
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expat

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Joined: 14 Mar 2007
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Location: Back in jolly old England

PostPosted: Tue Jun 12, 2007 1:54 pm    Post subject:
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Quote:
VSAM is not a database; It is an Access Method.

Do you know that DB2 keeps its data in VSAM files?


Another way of putting this, is that VSAM is an access method, a way to access the data, and VSAM structured file can be used to store DB2, IMS, CICS, and more, not only DB2.
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mkk157

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Joined: 17 May 2006
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PostPosted: Tue Jun 12, 2007 2:51 pm    Post subject: hi
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Hi Ofer71

Quote:
VSAM is not a database; It is an Access Method.

Do you know that DB2 keeps its data in VSAM files?



Expact

Quote:
Another way of putting this, is that VSAM is an access method, a way to access the data, and VSAM structured file can be used to store DB2, IMS, CICS, and more, not only DB2.



Can I know the real time exmples ot situation we use VSAM to store the data. I read this. But I never get a chance to work on VSAM till now. Please clarify my doubt.
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dick scherrer

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Joined: 23 Nov 2006
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Location: Inside the Matrix

PostPosted: Tue Jun 12, 2007 5:39 pm    Post subject:
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Hello,

There are millions of VSAM files around the world that are 10 -25 years old. Actually, in many places, the vsam environment is managed as a database environment - there just is no rdbms.

Many organizations have decided to implement new systems or upgrade older systems to take advantage of database technology. Often these new/upgraded systems still need to interact with existing systems.

If is very common for an application to use both vsam and database in the same code.
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