Re: IS and AS
From: Shakespeare <whatsin_at_xs4all.nl>
Date: Tue, 13 Jan 2009 12:12:23 +0100
Message-ID: <496c771c$0$201$e4fe514c_at_news.xs4all.nl>
>>>>> I was wondering what is the difference between IS and AS, in general
>>>>> PL/SQL code.
>>>>>
>>>>>
>>>>> For instance of FUNCTION book_t, how can oracle know if keyword ending
>>>>> the header is IS or AS;
>>>>> I mean if header returns SELF and declare result variable before BEGIN,
>>>>> or if header returns SELF AS RESULT and declare nothing before BEGIN.
>>>>>
>>>>>
>>>>> CREATE OR REPLACE TYPE BODY book_t
>>>>> AS
>>>>> CONSTRUCTOR FUNCTION book_t (id IN INTEGER,
>>>>> title IN VARCHAR2,
>>>>> isbn IN VARCHAR2,
>>>>> pages IN INTEGER)
>>>>> RETURN SELF AS RESULT
>>>>> IS
>>>>> BEGIN
>>>>> SELF.id := id;
>>>>> SELF.title := title;
>>>>> SELF.isbn := isbn;
>>>>> SELF.pages := pages;
>>>>> IF isbn IS NULL OR SELF.ck_digit_okay
>>>>> THEN
>>>>> RETURN;
>>>>> ELSE
>>>>> RAISE_APPLICATION_ERROR(-20000, 'ISBN ' || isbn
>>>>> || ' has bad check digit');
>>>>> END IF;
>>>>> END;
>>>>> ...
Date: Tue, 13 Jan 2009 12:12:23 +0100
Message-ID: <496c771c$0$201$e4fe514c_at_news.xs4all.nl>
O_TEXT schreef:
> Shakespeare a écrit : >> O_TEXT schreef: >>> Shakespeare a écrit : >>>> O_TEXT schreef:
>>>>> I was wondering what is the difference between IS and AS, in general
>>>>> PL/SQL code.
>>>>>
>>>>>
>>>>> For instance of FUNCTION book_t, how can oracle know if keyword ending
>>>>> the header is IS or AS;
>>>>> I mean if header returns SELF and declare result variable before BEGIN,
>>>>> or if header returns SELF AS RESULT and declare nothing before BEGIN.
>>>>>
>>>>>
>>>>> CREATE OR REPLACE TYPE BODY book_t
>>>>> AS
>>>>> CONSTRUCTOR FUNCTION book_t (id IN INTEGER,
>>>>> title IN VARCHAR2,
>>>>> isbn IN VARCHAR2,
>>>>> pages IN INTEGER)
>>>>> RETURN SELF AS RESULT
>>>>> IS
>>>>> BEGIN
>>>>> SELF.id := id;
>>>>> SELF.title := title;
>>>>> SELF.isbn := isbn;
>>>>> SELF.pages := pages;
>>>>> IF isbn IS NULL OR SELF.ck_digit_okay
>>>>> THEN
>>>>> RETURN;
>>>>> ELSE
>>>>> RAISE_APPLICATION_ERROR(-20000, 'ISBN ' || isbn
>>>>> || ' has bad check digit');
>>>>> END IF;
>>>>> END;
>>>>> ...
>>>> It's all a matter of parsing.... >>>> >>>> Shakespeare >>>> >>>> BTW: in many cases, AS and IS are interchangeable. >>> Is it possible to know on which rule PLSQL is based for parsing? >>> >>> >>> >> You could check out the syntax diagrams in the docs. >> >> Shakespeare > > such as > > http://download.oracle.com/docs/cd/A91202_01/901_doc/appdev.901/a89856/13_elems.htm >
Such is indeed
Shakespeare Received on Tue Jan 13 2009 - 12:12:23 CET