Re: Oracle Concepts Question

Thanks, I found that paragraph on intra-block chaining in the Concepts manual.

• rajXesh

"Ron" <support_at_dbainfopower.com> wrote in message news:<PYKdneruv9bzorjd4p2dnA_at_comcast.com>...
> "When a table has more than 255 columns, rows that have data after the 255th
> column are likely to be chained within the same block. This is called
> intra-block chaining. A chained row's pieces are chained together using the
> rowids of the pieces. With intra-block chaining, users receive all the data
> in the same block. If the row fits in the block, users do not see an effect
> in I/O performance, because no extra I/O operation is required to retrieve
> the rest of the row."
>
> Hope this answers the question.
>
> Regards,
>
> Ron
>
> DBA Infopower
>
> http://www.dbainfopower.com
>
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>
>
> "RK" <rajXesh_at_hotmail.com> wrote in message
> news:548b9514.0402061242.64b4b0dd_at_posting.google.com...
> > I was reading the Concepts manual and was puzzled by this sentence.
> > Can anyone elaborate on this:
> >
> > <snip> Tables are the basic unit of data storage in an Oracle
> > database. Database tables hold all user-accessible data. Each table
> > has columns and rows. Oracle stores each row of a database table
> > containing data for less than 256 columns as one or more row
> > pieces.</snip>
> >
> > What is this 256 column limit. I thought row chaining / migration
> > depended on row size.
> >
> >
> > See
 http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96524/c01_02intro.htm#20658
> >
> >
> > Thanks
> >
> > rajXesh
Received on Mon Feb 09 2004 - 02:43:41 CET