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Differences [message #239770] Wed, 23 May 2007 04:49 Go to next message
akkumar81
Messages: 144
Registered: February 2007
Location: india
Senior Member

Dear friends,

What is difference Between IOT and fulltable scan?
when these are using?

expecting your queries..

Arun..

Re: Differences [message #239771 is a reply to message #239770] Wed, 23 May 2007 04:52 Go to previous messageGo to next message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
To paraphrase your question, what is the difference between Sandals and Walking.

An IOT is a type of table, and a Full Table scan is an access path that the optimiser can choose when working out how best to get at the data in a table.
Re: Differences [message #239777 is a reply to message #239770] Wed, 23 May 2007 05:02 Go to previous messageGo to next message
Maaher
Messages: 7062
Registered: December 2001
Senior Member
Laughing I think you're confused Arun. An IOT is an Index Organized Table, a type of table. A Full Table Scan is a method of retrieving data. Those two have nothing to do with each other.

from a mysterious document
An index-organized table has a storage organization that is a variant of a primary B-tree. Unlike an ordinary (heap-organized) table whose data is stored as an unordered collection (heap), data for an index-organized table is stored in a B-tree index structure in a primary key sorted manner. Besides storing the primary key column values of an index-organized table row, each index entry in the B-tree stores the nonkey column values as well.



from the same mysterious document
This type of scan reads all rows from a table and filters out those that do not meet the selection criteria. During a full table scan, all blocks in the table that are under the high water mark are scanned. Each row is examined to determine whether it satisfies the statement's WHERE clause.


MHE
Re: Differences [message #239784 is a reply to message #239777] Wed, 23 May 2007 05:13 Go to previous message
Frank
Messages: 7880
Registered: March 2000
Senior Member
Maarten, please don't use these documents.
I don't want to read them.
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