Default Size of a CHAR Column

If you do not specify a size for a CHAR column, the default is 1. You can see what I mean in the example below, which I tested on Oracle 11.2:

SQL> create table t1

  2  (c1 char,

  3   c2 char(1))

  4  /

 

Table created.

 

SQL> desc t1

Name                       Null?    Type

-------------------------- -------- ------------------

C1                                  CHAR(1)

C2                                  CHAR(1)

 

SQL> 

However, if you rely on defaults like this and the software supplier changes them, you could be left with an application which does not work.