PLS-00201标识符必须声明

Question

This has got to be something really easy to fix, but for some reason I can't get it to work. I keep getting the error

PLS-00201: identifier 'ART' must be declared

My code is the following:

create or replace PROCEDURE question1(givenType IN VARCHAR, output OUT CHAR,output1 OUT CHAR)
AS
BEGIN
SELECT TITLE into output FROM CLASS where TYPE=givenType;
SELECT INSTRUCTOR into output1 FROM CLASS where TYPE=givenType;
DBMS_OUTPUT.PUT_LINE('The title of any classes with that type is: '|| output|| 'The instructor that taught each class is: ' || output1);
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE('No data found');
END;

I think the problem may be that when the user inputs "Art" the program takes it in as "ART" and since my table type is "Art" not "ART" then that's why I get the error. I just can't seem to know how to fix it to work. Any help guys?

Sorry guys I fell asleep last night here is the full error that I'm getting

Connecting to the database CS425 Spring 2015.
ORA-06550: line 6, column 16:
PLS-00201: identifier 'ART' must be declared
ORA-06550: line 6, column 3:
PL/SQL: Statement ignored
Process exited.
Disconnecting from the database CS425 Spring 2015.

Answer 1

PLS-00201: identifier 'ART' must be declared

I think the problem may be that when the user inputs "Art" the program takes it in as "ART" and since my table type is "Art" not "ART" then that's why I get the error.

It has nothing to do with the UPPER/LOWER case. The query is parsed as:

SELECT TITLE into output FROM CLASS where TYPE=ART;

If type is varchar type, then you must pass the value as a string, ie you must enclose it within single-quotation marks . Else, Oracle interprets it to be an identifier . So, it should be:

SELECT TITLE into output FROM CLASS where TYPE='ART';

For example,

SQL> SET SERVEROUTPUT ON
SQL> DECLARE
  2    o_dept NUMBER;
  3  BEGIN
  4    SELECT DEPTNO INTO o_dept FROM EMP WHERE ENAME=SCOTT;
  5    dbms_output.put_line(o_dept);
  6  END;
  7  /
  SELECT DEPTNO INTO o_dept FROM EMP WHERE ENAME=SCOTT;
                                                 *
ERROR at line 4:
ORA-06550: line 4, column 50:
PL/SQL: ORA-00904: "SCOTT": invalid identifier
ORA-06550: line 4, column 3:
PL/SQL: SQL Statement ignored


SQL> DECLARE
  2    o_dept NUMBER;
  3  BEGIN
  4    SELECT DEPTNO INTO o_dept FROM EMP WHERE ENAME='SCOTT';
  5    dbms_output.put_line(o_dept);
  6  END;
  7  /
20

PL/SQL procedure successfully completed.

SQL>

And, it is not a good idea to use reserved keywords as object names. TYPE is a reserved keyword.