SQL>
SQL> variable x number
SQL> variable y varchar2(8)
SQL>
SQL> execute :x := 7566
PL/SQL procedure successfully completed.
SQL> execute :y := 'ADMIN'
PL/SQL procedure successfully completed.
SQL>
SQL> print x y
X
------
7566
Y
--------------------------------
ADMIN
SQL> variable
variable x
datatype NUMBER
variable y
datatype VARCHAR2(8)
SQL>