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How an Alternate index defined as "Non-Unique" Wor

 
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THINKSRINIII
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PostPosted: Mon Mar 16, 2009 1:33 pm    Post subject: How an Alternate index defined as "Non-Unique" Wor
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Hi Guys,

I have just come accross a question while taking up a test for VSAM basics. Could you please explain me how an A.I defined as "Non-Unique" works and what is the answer in this case. I have attached the question.

Am a newbie to VSAM.. Please adjust if the question is too simple.


Code:
Primary Key is defined to be the Part Number and sorted
Part_Number Assembly Description
2001        Bicycle  Wheel
2003        Table    Top
2002        Bicycle  Seat
2001        Table    Leg
2004        Table    Brackets




Thanks.
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expat

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PostPosted: Mon Mar 16, 2009 2:53 pm    Post subject:
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Post the question and not an attachment as many people can not open attachments.
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enrico-sorichetti

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PostPosted: Mon Mar 16, 2009 3:10 pm    Post subject: Reply to: How an Alternate index defined as "Non-Unique
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please review You understanding of the question posed

You ask about alternate index, but the data You posted has a primary key

from the VSAM point of view and from BOM ( bill of material processing ) point of view

there are conflicts
1) (VSAM) the primary key must be unique

2) (BOM)
... its silly to have the same part number for a bicycle wheel and a table leg

review the data, or correct the typing errors

to give sensible answers we need sensible questions and data icon_biggrin.gif
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THINKSRINIII
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PostPosted: Mon Mar 16, 2009 3:30 pm    Post subject:
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Hi E.S

Apologise for the Typo error..

Here's the question again.. For the data shown on the topic..

Code:

Primary Key is defined to be the Part Number and sorted
Part Number    Assembly   Description
2001   Bicycle   Wheel
2003   Table   Top
2002   Bicycle   Seat
2000   Table   Leg
2004   Table   Brackets


With an Alternate index defined as “Non-Unique”, which of the following would be the structure of A.I?

Option 1
 
Alternate Key   Table      Bicycle    Bicycle   Table  Table
Primary Key     2000       2001       2002   2003   2004

Option 2
Assembly      Description         Part Number
Bicycle        Seat                   2002
Bicycle        Wheel                   2001
Table        Brackets    2004
Table         Leg                   2000
Table         Top                   2003

Option 3
Assembly  Part number
Bicycle      2001 2002
Table        2000 2003 20004

Option 4
Assembly             Part number
Bicycle            2001
Bicycle            2002
Table             2000
Table             2003   
Table             2004

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enrico-sorichetti

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PostPosted: Mon Mar 16, 2009 3:41 pm    Post subject: Reply to: How an Alternate index defined as "Non-Unique
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an alternate index does not have a structure

its simply a way of presenting data in a different order

to get a better grasp of how things might look themselves
You might ...

define a cluster
load it with Your data
print the base cluster

define an alternate index
build the laternate index

define the path
print the path to see how the data looks like


here is a pointer to a thread with all the jcl needed
it should be fairly easy to modify it for the sample You posted
http://www.ibmmainframes.com/viewtopic.php?t=29269&postdays=0&postorder=asc&start=17
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THINKSRINIII
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PostPosted: Mon Mar 16, 2009 4:59 pm    Post subject:
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Hi E.S,

Many thanks for that. But, if you were to select an option from the list? what would you do. My instinct seeing the question also was that A.I will not be having a aspecific structure.

Cheers
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Bill O'Boyle

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PostPosted: Mon Mar 16, 2009 5:09 pm    Post subject: Reply to: How an Alternate index defined as "Non-Unique
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Check out Gilbert Saint-Flour's link regarding Alternate Indexes -

http://gsf-soft.com/Documents/VSAM-AIX.shtml

Regards,
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Robert Sample

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PostPosted: Mon Mar 16, 2009 5:38 pm    Post subject:
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Option 3 is the closest to the way non-unique alternate indexes work; the alternate index field is followed by the primary keys that have that particular alternate index value within the record.
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enrico-sorichetti

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PostPosted: Mon Mar 16, 2009 5:53 pm    Post subject: Reply to: How an Alternate index defined as "Non-Unique
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here are the results for the test I ran for You

jcl
Code:

000001 //ENRICOA JOB (H001),'ZKSDS1',NOTIFY=ENRICO,
000002 //             CLASS=A,MSGCLASS=X,MSGLEVEL=(1,1)
000003 //* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
000004 //*            DSN=ENRICO.MF.JCLLIB(ZKSDS1)
000005 //* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
000006 //*
000007 //AMS      EXEC PGM=IDCAMS
000008 //SYSPRINT   DD SYSOUT=*
000009 //KSDSDATA   DD *
000010 2000      TABLE     LEG
000011 2001      BICYCLE   WHEEL
000012 2002      BICYCLE   SEAT
000013 2003      TABLE     TOP
000014 2004      TABLE     BRACKETS
000015 //*
000016 //SYSIN      DD *
000017   DELETE (ENRICO.MF.KSDS.PATH) PATH    PURGE
000018   SET LASTCC=0
000019   DELETE (ENRICO.MF.KSDS.AIX)  AIX     PURGE
000020   DELETE (ENRICO.MF.KSDS.CL)   CLUSTER PURGE
000021   SET LASTCC=0
000022   SET MAXCC=0
000023
000024   DEFINE CLUSTER( -
000025                 NAME(ENRICO.MF.KSDS.CL) -
000026                 INDEXED KEYS(10 0) -
000027          SHR(2 3) CYL(1 1) VOL(MFVSAM) ) -
000028          DATA(    -
000029                 RECSZ(80 80) CISZ(4096) FREESPACE(0 0) )
000030
000031   IF MAXCC  = 0 THEN -
000032      REPRO INFILE(KSDSDATA) OUTDATASET(ENRICO.MF.KSDS.CL)
000033
000034   IF MAXCC  = 0 THEN -
000035      PRINT INDATASET(ENRICO.MF.KSDS.CL) DUMP
000036
000037   IF MAXCC  = 0 THEN -
000038      DO
000039         DEFINE AIX( -
000040                   NAME(ENRICO.MF.KSDS.AIX) -
000041                   RELATE(ENRICO.MF.KSDS.CL) -
000042                   KEYS(10 10) -
000043                   SHR(2 3) CYL(1 1) VOL(MFVSAM) ) -
000044               DATA(    -
000045                   RECSZ(10 2048) CISZ(4096) FREESPACE(0 0) )
000046      END
000047
000048   IF MAXCC  = 0 THEN -
000049      DO
000050         BLDINDEX INDATASET(ENRICO.MF.KSDS.CL) -
000051                  OUTDATASET(ENRICO.MF.KSDS.AIX)
000052      END
000053
000054   IF MAXCC  = 0 THEN -
000055      PRINT INDATASET(ENRICO.MF.KSDS.AIX) DUMP
000056
000057   IF MAXCC  = 0 THEN -
000058      DO
000059         DEFINE PATH( -
000060                    NAME(ENRICO.MF.KSDS.PATH) -
000061                    PATHENTRY(ENRICO.MF.KSDS.AIX) )
000062      END
000063
000064   IF MAXCC  = 0 THEN -
000065      PRINT INDATASET(ENRICO.MF.KSDS.PATH) DUMP
000066 /*


sysout
Code:

-LISTING OF DATA SET -ENRICO.MF.KSDS.CL
0KEY OF RECORD - F2F0F0F0404040404040
 000000  F2F0F0F0 40404040 4040E3C1 C2D3C540   40404040 D3C5C740 40404040 40404040   *2000      TABLE     LEG         *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 404040400  *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - F2F0F0F1404040404040
 000000  F2F0F0F1 40404040 4040C2C9 C3E8C3D3   C5404040 E6C8C5C5 D3404040 40404040   *2001      BICYCLE   WHEEL       *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - F2F0F0F2404040404040
 000000  F2F0F0F2 40404040 4040C2C9 C3E8C3D3   C5404040 E2C5C1E3 40404040 40404040   *2002      BICYCLE   SEAT        *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - F2F0F0F3404040404040
 000000  F2F0F0F3 40404040 4040E3C1 C2D3C540   40404040 E3D6D740 40404040 40404040   *2003      TABLE     TOP         *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - F2F0F0F4404040404040
 000000  F2F0F0F4 40404040 4040E3C1 C2D3C540   40404040 C2D9C1C3 D2C5E3E2 40404040   *2004      TABLE     BRACKETS    *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0IDC0005I NUMBER OF RECORDS PROCESSED WAS 5

-LISTING OF DATA SET -ENRICO.MF.KSDS.AIX
0KEY OF RECORD - C2C9C3E8C3D3C5404040
000000  010A0002 0AC2C9C3 E8C3D3C5 404040F2   F0F0F140 40404040 40F2F0F0 F2404040   *.....BICYCLE   2001      2002   *
000020  404040                                                                      *                                *

0KEY OF RECORD - E3C1C2D3C54040404040
000000  010A0003 0AE3C1C2 D3C54040 404040F2   F0F0F040 40404040 40F2F0F0 F3404040   *.....TABLE     2000      2003   *
000020  404040F2 F0F0F440 40404040 40                                               *   2004                         *

0IDC0005I NUMBER OF RECORDS PROCESSED WAS 2

-LISTING OF DATA SET -ENRICO.MF.KSDS.PATH
0KEY OF RECORD - C2C9C3E8C3D3C5404040
 000000  F2F0F0F1 40404040 4040C2C9 C3E8C3D3   C5404040 E6C8C5C5 D3404040 40404040   *2001      BICYCLE   WHEEL       *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - C2C9C3E8C3D3C5404040
 000000  F2F0F0F2 40404040 4040C2C9 C3E8C3D3   C5404040 E2C5C1E3 40404040 40404040   *2002      BICYCLE   SEAT        *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - E3C1C2D3C54040404040
 000000  F2F0F0F0 40404040 4040E3C1 C2D3C540   40404040 D3C5C740 40404040 40404040   *2000      TABLE     LEG         *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - E3C1C2D3C54040404040
 000000  F2F0F0F3 40404040 4040E3C1 C2D3C540   40404040 E3D6D740 40404040 40404040   *2003      TABLE     TOP         *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0KEY OF RECORD - E3C1C2D3C54040404040
 000000  F2F0F0F4 40404040 4040E3C1 C2D3C540   40404040 C2D9C1C3 D2C5E3E2 40404040   *2004      TABLE     BRACKETS    *
 000020  40404040 40404040 40404040 40404040   40404040 40404040 40404040 40404040   *                                *
 000040  40404040 40404040 40404040 40404040                                         *                                *

0IDC0005I NUMBER OF RECORDS PROCESSED WAS 5


so the right answer to a badly posed question
( incompetent interviewer)

would be ...
3 - for the content of the AIX component
4 - for the order of retrieval using the PATH
as per my test
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