Re: Database compression..?

Mark Norris wrote in message <7ef1mp$6o8$1_at_mailusr.wdf.sap-ag.de>...
>Hello, after a few hours unsuccessful surfing yesterday, i was wondering if
>anyone could point me in the right direction.
>
>I'm trying to find out information about the compression of empty fields.
>i.e. if i have a table with lots of columns, but most of them are empty,
>what does ORACLE do, does it store the empty space.?
>
>Any information would be appreciated...
>
>Mark
>
>

For Oracle 7 (a field is the intersection of a row and a column): If an empty field is the last field, or if the empty field has only empty fields "behind" it, it uses no space, otherwise is uses 1 byte.

This is because the row header contains a value that specifies the column # of the last non-empty field. An empty field "in front of" the last non-empty field has a header which says that the field is empty.

I think it's the same in Oracle 8.

Regards,

Roy Brokvam
roy.brokvam_at_conax.com Received on Wed Apr 07 1999 - 03:32:51 CDT