SQL & PL/SQL

Hi there,

Can anyone tell me whether it is possible to evaluate an arbitrary expression dynamically in PL/SQL.
I am using Oracle9i Enterprise Edition Release 9.2.0.6.0.

I would like to be able to do something like:

DECLARE
    MyVar                        VARCHAR2(9);
    MyExpression                 VARCHAR2(99);
    MyResult                     BOOLEAN := FALSE;
BEGIN
    MyVar                        := 'Yes';
    MyExpression                 := 'MyVar = ''Yes''';
    IF MyExpression                                                -- <== this does not work: PLS-00382: expression is of wrong type
    THEN
        MyResult := TRUE;
    END IF;
    IF MyResult
    THEN
        DBMS_OUTPUT.PUT_LINE(MyExpression||' is true');
    ELSE
        DBMS_OUTPUT.PUT_LINE(MyExpression||' is false');
    END IF;
END;
/

One way I tried to solve my problem is using dynamic SQL, but I do not think this is the answer.
For instance:

DECLARE
    MyVar                        VARCHAR2(9);
    MyExpression                 VARCHAR2(99);
    MySQLStatement               VARCHAR2(999);
    MyResultString               VARCHAR2(5) := 'FALSE';
    MyResult                     BOOLEAN := FALSE;
BEGIN
    MyVar          := 'Yes';
    MyExpression   := ':MyVar = ''Yes''';
    MySQLStatement := 'SELECT ''TRUE'' FROM DUAL WHERE '||MyExpression;
    BEGIN
        EXECUTE IMMEDIATE MySQLStatement INTO MyResultString USING MyVar;
    EXCEPTION
    WHEN NO_DATA_FOUND
    THEN
        MyResultString := 'FALSE';
    END;
    MyResult := MyResultString = 'TRUE';
    IF MyResult
    THEN
        DBMS_OUTPUT.PUT_LINE(MyExpression||' is true');
    ELSE
        DBMS_OUTPUT.PUT_LINE(MyExpression||' is false');
    END IF;
END;
/

The problem with this approach is that the USING clause must refer to a specific variable.

Anyone has a bright idea?

Thanks, Jaap