Getting the max length

Question

i am using pl/sql and i need to do some validation regarding the max length of the string. but the problem is that i have to refer back to the database for the length so that if the database change, my code don't change.
is there any way to get the max length in the field of the table?
eg:
lets say i got a table call Person with column Name(varchar2(66)) and Sex(char(1))
so how i retrieve the max length of the field Name?
thanks

Answer 1

It's quite simple. We can use the PL/SQL %TYPE in our declarations. Check it out...
SQL> CREATE TABLE small1 (col1 NUMBER, col2 VARCHAR2(3))
  2  /
Table created.
SQL>
SQL> CREATE OR REPLACE PROCEDURE small1_api (pv_string IN VARCHAR2)
  2  AS
  3      l_col2 small1.col2%TYPE;
  4  BEGIN
  5      l_col2 := pv_string;
  6      INSERT INTO small1 (col1, col2)
  7      VALUES (a12.NEXTVAL, l_col2);
  8  EXCEPTION
  9      WHEN value_error THEN
10          dbms_output.put_line('oops! string is too long');
11  END;
12  /
Procedure created.
SQL> EXEC small1_api('APC')
PL/SQL procedure successfully completed.
SQL> EXEC small1_api('APC4')
oops! string is too long
PL/SQL procedure successfully completed.
SQL>
SQL> ROLLBACK
  2  /
Rollback complete.
SQL> ALTER TABLE small1 MODIFY (col2 VARCHAR2(4))
  2  /
Table altered.
SQL> ALTER PROCEDURE  small1_api COMPILE
  2  /
Procedure altered.
SQL>
SQL> EXEC small1_api('APC4')
PL/SQL procedure successfully completed.
SQL> EXEC small1_api('APC45')
oops! string is too long
PL/SQL procedure successfully completed.
SQL> Cheers, APC