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babun
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Joined: 03 Aug 2005 Posts: 9 Location: bangalore
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how the cobol program look alike when we r using Vsam ksds? what r all the necessary action on cobol pgm? |
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babun
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Joined: 03 Aug 2005 Posts: 9 Location: bangalore
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can we use SELECT * FROM ------; query in Embedded SQL? if we can why ? if we can't why?
pls let me know folks? |
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thanooz
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Joined: 28 Jun 2005 Posts: 99
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hi
babum
when you are using ksds
the main consideration on
file control
select filename assign to jcldd
organiztion is indexed
access mode sequential/random/dynamic
record key is file-key-field
alternate key is file-alternate-key field.
if it is sequential access no bother of record key and alternate key.
thanks,
thanooz. |
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thanooz
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Joined: 28 Jun 2005 Posts: 99
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hi babu
we cont in embeded sql. because it gives error. |
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Ravi Gopal
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Joined: 04 Aug 2005 Posts: 3
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Hi Babun,
The reason for not using SELECT * FROM query in the program is:
1.If the table structure is changed (a field is added), the program will have to be modified.
2.Program might retrieve the columns which it might not use, leading on I/O over head.
Cheers
Ravi |
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babun
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Joined: 03 Aug 2005 Posts: 9 Location: bangalore
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Thanks ravi
thank you for your answer..
it's clear |
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thanooz
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Joined: 28 Jun 2005 Posts: 99
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hi babu
For three reasons:
If the table structure is changed (a field is added), the program will have to be modified
Program might retrieve the columns which it might not use, leading on I/O over head.
The chance of an index only scan is lost.
thanks,
thanooz. |
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