Doubt in Partitioning index..?



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Doubt in Partitioning index..?

Postby gokulNmf » Thu Oct 29, 2009 2:40 pm

HI friends,

i was reading 'Introduction to DB2 for z/OS' for learning about the partitioned index. in that Chapter 7( Implementation of your database design) there are points which tells the charecteristics of the partitioned table, in that a point tells "A partitioning index can be partitioned or nonpartitioned". i could not able to understand this point :? , is it reffering to the table controlled partitioning?
Cheers,
Gokul
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Re: Doubt in Partitioning index..?

 

Re: Doubt in Partitioning index..?

Postby GuyC » Thu Oct 29, 2009 8:38 pm

no.
partitioning index means : an index which is used to decide in which partition (of the table) the data is stored . ie. the first columns in the index are equal to the partition key
nonpartitioned index means an index that has references to all rows of the table and has one Indexpart.
partitioned index is an index which has different parts/indexspaces with in each part references rows of a corresponding tablepart.

I guess you could create an index of which the first columns are equal to the partition key and wouldn't define it partitioned, but I can see only disadvantages.

a partioned index that isn't partitioning (aka DPSI ) can not be defined unique.
I can explain it to you, but i can not understand it for you.
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Re: Doubt in Partitioning index..?

Postby GuyC » Thu Oct 29, 2009 8:46 pm

If an index defined with 'PARTITION BY' :
your table is still indexpartitioned

- That index is also called partitioning index and will always be partitioned.
- You can't have other indexes that are partitioned on an indexpartitioned table.
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