Re: Not Nulls grouped as first column.....

The reason for not nulls to the front rule is performance and upkeep overhead. Oracle does not have to read the whole record during a query if the data is at the front of the record. Updates to the "nullable" columns pushes the required data deeper into the record causing more update processing time.

Tao36 (tao36_at_aol.com) wrote:
: I've always been told to keep all my "not null" columns together at the front
: of the table. However, due to the severe effects of aging (or possibly
: environmental contaminants) I can't remember why.
 

: I have a situation in which it is a lot easier for me to "alter" a table,
: adding a new "not null" column to the end, as opposed to "dropping" the table
: and recreating it with the new column grouped at the front with all his "not
: null" buddies.
 

: What are the effects of not grouping my "not nulls"? Catastrophic? Mild
: annoyance? Was it anal to keep them together in the first place?
 

: Thanks for any enlightenment.
: Kevin

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