"Paul Pruchnik" <paulrp_at_earthlink.net> wrote in message news:<5eria.3978$ey1.309583_at_newsread1.prod.itd.earthlink.net>...
> Greetings,
> What is the savings of CHAR(4) vs VARCHAR(4) for storing a 4 (required)
> character code? What is the overhead in using VARCHAR for fields of required
> length?
> Thanks,
> -Paul Pruchnik
The correct question is: "What is the overhead in using CHAR". If Oracle
was designed from scratch to work with both CHAR and VARCHAR, CHAR operations
probably would be faster. But initially, until V7, Oracle had CHAR datatype
which was the same as current VARCHAR2. And, judging by behavior, CHAR
datatype uses the same code as VARCHAR2, adjusted to fixed length. Hence
CHAR still has a length descriptor.
There is a conceptual difference between CHAR and VARCHAR2 when doing
string comparisons. Unless all your data is exactly 4 characters,
comparison operations might return different results when using CHAR vs
VARCHAR2. It's described in SQL reference documentation.
There is no significant difference in performance.
Received on Wed Apr 02 2003 - 13:20:45 CST
