In SQL, you call it like this with the parentheses. This type of call mechanic is required for user-definted object types that are instantiable.

SQL> SELECT sys_guid() FROM dual;

The PL/SQL syntax returns a different value because each call returns a unique value.

BEGIN
  DBMS_OUTPUT.put_line('['|sys_guid||']');
END;
/

Laurent, while you know all this other don’t and I figured it might help somebody. If you’ve any followup comments, they’re always appreciated.

Here’s a quick little example of the object type, and it’s call semantics. The first step is to create an object type that returns an instance of itself.

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CREATE OR REPLACE TYPE hello_there IS OBJECT
( who VARCHAR2(20)
, CONSTRUCTOR FUNCTION hello_there
  RETURN SELF AS RESULT
, CONSTRUCTOR FUNCTION hello_there
  ( who VARCHAR2 )
  RETURN SELF AS RESULT )
INSTANTIABLE NOT FINAL;
/

After defining the object type, you create the body, like this:

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CREATE OR REPLACE TYPE BODY hello_there IS
 
  CONSTRUCTOR FUNCTION hello_there RETURN SELF AS RESULT IS
    hello HELLO_THERE := hello_there('Generic Object.');
  BEGIN
    self := hello;
    RETURN;
  END hello_there;
 
  CONSTRUCTOR FUNCTION hello_there (who VARCHAR2) RETURN SELF AS RESULT IS
  BEGIN
    self.who := who;
    RETURN;
  END hello_there;
 
END;
/

If you attempt to call it without parentheses in a SQL statement, it’ll fail like so …

SELECT hello_there FROM dual
       *
ERROR at line 1:
ORA-00904: "HELLO_THERE": invalid identifier

You should note that the error message is quite different than that received with the CALL triggered ORA-06576 error. If you provide paraentheses, like this

SELECT hello_there() FROM dual;

it’ll succeed with the following return value:

HELLO_THERE()(WHO)
------------------------------
HELLO_THERE('Generic Object.')

There’s no equivalent CALL syntax into a bind variable because you can’t define a bind variable of a user-defined type (e.g., object type). More on the right way to manage Oracle object types is found in Chapter 14 of Oracle Database 11g PL/SQL Programming.

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