Re: Index organised table

Pradeep wrote:
> I am reading tom kytes Expert ....
>
> 1. I am unable to understand the statement
> "with IOT logical I/O would be the same, the physical I/O would be
> less"
> May be because i don't know how data is physically stored with IOT.
>
> Suppose if I have a Index organised table with colum "ename", then is
> it that all the blocks containing enames begining with "A" will be
> together followed by the very next block with next sequence of enames,
> or is it sorted within the block ??
>
> 2. It also states that in IOT data must go where it belongs. now
> suppose if in the above table if i have a block with all rows with
> enames beginning with "A" except one which begins with "B". Now if i
> add a row with ename beginning with "A" then what happens ?
>
>
> Thanks

In a b-tree index, you have the key values accompanied by the rowids that indicate where the row is physically stored. The structure of a b-tree index means that the keys are stored in sort order.

In an IOT, the index is the table. You have the key values accompanied by the rest of the row. That has some implications concerning the order of physical row storage, amongst other things. Received on Fri Dec 02 2005 - 18:30:01 CST