Friday, January 7, 2011

Partitioning a Table

Partitioning enables tables and indexes or index-organized tables to be subdivided into smaller manageable pieces and these each small piece is called a "partition". From an "Application Development" perspective, there is no difference between a partitioned and a non-partitioned table. Oracle introduced partitioning with 8.0. With this version only, " Range Partitioning" was supported. Then with Oracle 8i " Hash and Composite Partitioning" was also introduced and with 9i " List Partitioning", it was introduced with lots of other features with each upgrade. Each method of partitioning has its own advantages and disadvantages and the decision which one to use will depend on the data and type of application. Also one can MODIFY , RENAME, MOVE, ADD, DROP, TRUNCATE, SPLIT partitions.

Advantages of using Partition’s in Table

1. Smaller and more manageable pieces of data ( Partitions )
2. Reduced recovery time
3. Failure impact is less
4. import / export can be done at the " Partition Level".
5. Faster access of data
6. Partitions work independent of the other partitions.
7. Very easy to use

Types of Partitioning Methods

1. RANGE Partitioning
2. HASH Partitioning
3. List Partitioning ( Only with 9i)
4. Composite Range-Hash Partitioning
5. Composite Range-List Partitioning ( Only with 9i) 

For More detail : Example  1   Example 2   Example 3   Example 4

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