What is the major difference between Varchar2 and char

Question

Creating Table:

CREATE TABLE test (
charcol    CHAR(10),
varcharcol VARCHAR2(10));

SELECT LENGTH(charcol), LENGTH(varcharcol) FROM test;
         


        

Answer 1

CHAR

CHAR should be used for storing fix length character strings. String values will be space/blank padded before stored on disk. If this type is used to store varibale length strings, it will waste a lot of disk space.

VARCHAR2

VARCHAR2 is used to store variable length character strings. The string value's length will be stored on disk with the value itself.

And

At what times we use both?

Its all depend upon your requirement.