Re: VARCHAR2 vs CHAR

Hi Jeffrey,

    There is one set of circumstances under which I use CHAR:

        For data elements which are added into a row after the rest of the row has been inserted in a table. This is because CHAR reserves all of the space needed for a data element at the time the row is inserted into the table while VARCHAR2 only reserves and uses enough space to contain the value at the time the row is inserted. The use of CHAR , on my part, is to avoid chained rows. A chained row is created when a table is updated and there isn't sufficient space in the original location to contain the additional information. Chained rows result in additional disk accesses and since you can execute hundreds of thousands or perhaps even millions of instructions in the time it takes to do one I/O operation.

    Please bear in mind that my preference is based on my being more concerned about getting good performance than saving disk space.

regards

Jerry

Jeffrey A. Thompson wrote in message <7007t9$ojo$1_at_supernews.com>...
>I'm new to ORACLE. Is there a rule of thumb of when to use VARCHAR2
instead
>of CHAR.
>
>Thanks.
>
>
Received on Wed Oct 14 1998 - 12:08:07 CDT