CHAR

CHAR(n) type stores a fixed-length alphanumeric value. The n indicates how long the value will be. The CHAR(n) data type pads any remaining unused space with blanks and keep the length n. The n is optional. Its default value is 1. The maximum allowed value for n is 2000.

CREATE TABLE positions(  
   id         NUMBER,
   flag       CHAR(1)
);