Oracle PL/SQL Tutorial/PL SQL Data Types/CONSTANT

Constants cannot be changed

   <source lang="sql">

SQL> SQL> SET SERVEROUTPUT ON SQL> DECLARE

 2     v_first_name CONSTANT VARCHAR2(50) := "Ron";
 3  BEGIN
 4     v_first_name := "Ronald";
 5  EXCEPTION
 6     WHEN OTHERS
 7     THEN
 8        DBMS_OUTPUT.PUT_LINE(SQLERRM);
 9  END;
10  /
  v_first_name := "Ronald";
  *

ERROR at line 4: ORA-06550: line 4, column 4: PLS-00363: expression "V_FIRST_NAME" cannot be used as an assignment target ORA-06550: line 4, column 4: PL/SQL: Statement ignored

SQL></source>