关于接口的无敌解释

1) Function and Procedure overloading

1@@@@ overloading procedure and function, both.

SYS@ocm> !cat tmp.sql

DECLARE --Modularization

FUNCTION value_ok ( date_in IN DATE ) RETURN BOOLEAN IS

BEGIN

RETURN (date_in <= SYSDATE);

END;

FUNCTION value_ok ( number_in IN NUMBER ) RETURN BOOLEAN IS

BEGIN

RETURN number_in > 0;

END;

PROCEDURE value_ok ( number_in IN NUMBER ) IS

BEGIN

IF number_in > 0 THEN

DBMS_OUTPUT.put_line(

'Function and Procedure could be overloading each other'

);

END IF;

END;

BEGIN

/* Calling first function */

IF value_ok( to_date('1999-01-01','yyyy-mm-dd') ) THEN

DBMS_OUTPUT.put_line('The date was already passed.');

END IF;

/* Calling second function */

IF value_ok(1) THEN

DBMS_OUTPUT.put_line('The number is greater then 0.');

END IF;

/* Calling third procedure */

value_ok(1);

END;

/

SYS@ocm> @tmp.sql

The date was already passed.

The number is greater then 0.

Function and Procedure could be overloading each other

PL/SQL procedure successfully completed.
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