´ÙÀ½ ÀÌÀü Â÷·Ê

4. PL/pgSQL

4.1 PL/pgSQL 1 (PL/pgSQL󸮱⠵î·Ï)

1. Procedure Language

Postgres 6.3 ¹öÁ¯ ºÎÅÍ PostgreSQLÀº procedural Language(PL)¸¦ Áö¿øÇϱ⠽ÃÀÛÇß´Ù. ÀÌ°ÍÀº PostgreSQL¸¸ÀÇ Æ¯º°ÇÑ °æ¿ì·Î¼­ oracle ÀÇ PL/SQL°ú ºñÀ¯µÉ ¼ö ÀÖ´Ù. ÇÏÁö¸¸ Ư¼öÇÑ ¾ð¾îÀÎ PostgreSQLÀÇ PLÀº PostgreSQL¿¡ ³»ÀåµÈ°Í ¾Æ´Ï°í ¸ðµâÈ­µÈ Handler¸¦ ´Ù½Ã µ¥ÀÌŸº£À̽º¿¡ µî·ÏÀ» ÇØÁÖ¾î¾ß ÇÑ´Ù. ±×·¸Áö ¾ÊÀ¸¸é µ¥ÀÌŸº£À̽º´Â PL ·Î ¾² ¿©Áø functionÀÇ ³»¿ëÀ» ÀÌÇØÇÒ ¼ö ¾øÀ» °ÍÀÌ´Ù. °á·ÐÀûÀ¸·Î 󸮱â´Â °øÀ¯°´Ã¼·Î¼­ ÄÄÆÄÀÏµÇ¸ç µ¿ÀûÀ¸·Î Load µÇ´Â Ưº°ÇÑ ¾ð¾î ó¸® ±â´ÉÀÌ´Ù.

¿©±â¼­´Â PL HandlerÀÇ µî·ÏÀÇ ¿¹·Î¼­ PLÀÇ ÇÑÁ¾·ùÀÎ PL/pgSQL ¾ð¾î¸¦ µî·ÏÇÏ°Ú´Ù.

Installing Procedural Languages

°øÀ¯°´Ã¼ÀΠ󸮱â´Â ÄÄÆÄÀÏµÈ ÈÄ ÀνºÅçµÇ¾î¾ß Çϴµ¥ µðÆúÆ®·Î PL/pgSQL Àº PostgreSQL ¼³Ä¡½Ã ÀÚµ¿À¸·Î ÄÄÆÄÀϵÈÈÄ ¶óÀ̺귯¸® µð·ºÅ丮¿¡ ³õ¿©Áø´Ù. ´Ù ¸¥ 󸮱âÀÎ PL/Tcl Àº PostgreSQL ÄÄÆÄÀϽà ¸í½ÃÀûÀ¸·Î ¼³Á¤µÇ¾î¾ßÁö¸¸ ÄÄÆÄ ÀÏµÇ¸ç ¶óÀ̺귯¸® µð·ºÅ丮¿¡ ³õ¿©Áø´Ù. ¶óÀ̺귯¸® µð·ºÅ丮´Â ¼³Ä¡µÇ¾îÁú PostgreSQLÀÇ ¹Ù·Î ¹ØÀÇ lib ÀÌ´Ù. ¿¹¸¦ µé¾î PostgreSQLÀÇ Àý´ë°æ·Î°¡ ´ÙÀ½°ú °°´Ù°í ÇÏÀÚ.

/usr/local/pgsql

±×·¯¸é ¶óÀ̺귯¸® µð·ºÅ丮ÀÇ Àý´ë°æ·Î´Â ´ÙÀ½°ú °°´Ù.

/usr/local/pgsql/lib

PL/pgSQL ¾ð¾î 󸮱⸦ ¼³Ä¡Çϱâ À§Çؼ­´Â ¸ÕÀú À§ÀÇ ¶óÀ̺귯¸® µð·ºÅ丮¿¡¼­ "plpgsql.so" ¸¦ ¸ÕÀú È®ÀÎÇÏ¿©¾ß ÇÑ´Ù.

È®ÀÎ ÈÄ CREATE FUNCTION ¿Í CREATE PROCEDURAL LANGUAGE ¿¡ ÀÇÇØ °¢ µ¥ÀÌŸº£À̽º ¿¡¼­ µî·ÏÀ» ÇÏ¿©¾ß ÇÑ´Ù. °¢ µ¥ÀÌŸº£À̽º¿¡¼­ µî·ÏÀ» ÇÏÁö¾Ê°í ÀÏ°ýÀûÀ¸·Î ó¸®ÇÏ°í ½Í´Ù¸é PostgreSQL ÀÇ Æ¯º°Èù µ¥ÀÌŸº£À̽ºÀÎ "template1" ¿¡¼­ µî·ÏÀ» ÇϸéµÈ´Ù. template1 ¿¡¼­ µî·ÏÀÌ µÇ¾ú´Ù¸é Â÷ÈÄ »ý¼ºµÇ´Â µ¥ÀÌŸº£À̽º¿¡´Â ÀÚµ¿ÀûÀ¸·Î 󸮱Ⱑ µî·ÏµÈ´Ù.

PL/pgSQL 󸮱⠵î·Ï ¿¹Á¦

 
 [postgres@nogadax postgresql]psql template1
  template1=>
  template1=> CREATE  FUNCTION  plpgsql_call_handler()  RETURNS  OPAQUE
  template1-> AS  ' /usr/local/pgsql/lib/plpgsql.so ' 
  template1-> LANGUAGE  'C' ;
  template1=> 
  template1=> CREATE  TRUSTED  PROCEDURAL  LANGUAGE  'plpgsql'
  template1-> HANDLER  plpgsql_call_handler
  template1-> LANCOMPILER  'PL/pgSQL' ;
  template1=> 
  template1=> CREATE  DATABASE  nogadax ; 
  template1=> 

ȤÀº À§ÀÇ ¹®À» È­ÀÏ·Î ÀúÀåÇÑÈÄ \i ¸¦ »ç¿ëÇÒ ¼ö ÀÖ´Ù.

 template1=> \i   /usr/local/src/plsql_inst.sql

"CREATE TRUSTED PROCEDURAL LANGUAGE" ¿¡¼­ TRUSTED Å°¿öµå´Â PostgreSQL ÀÇ ½´ÆÛÀ¯Àú ±ÇÇÑÀÌ ¾ø´Â ÀÏ¹Ý À¯Àú°¡ "CREATE FUNCTION" À̳ª "CREATE TRIGGER" ¹®À» »ç¿ëÇÒ ¶§ µî·Ï µÈ procedure language(PL) ¸¦ »ç¿ëÇÒ ¼ö ÀÖµµ·Ï ÇØÁØ´Ù.

2. PL/pgSQL

PL/pgSQL Àº PostgreSQL µ¥ÀÌŸº£À̽º ½Ã½ºÅÛ¿¡¼­ "Loadable Procedural Language"ÀÌ´Ù. ÀÌ ÆÐÅ°Áö´Â Jan Wieck ¿¡ÀÇÇØ ÀÛ¼ºµÇ¾ú´Ù.

OVERVIEW

   1. PL/pgSQL Àº function À̳ª trigger procedure ¸¦ ¸¸µå´Âµ¥ »ç¿ëµÇ¾î Áú ¼ö ÀÖ´Ù.
   2. SQL ¹®¿¡ Á¦¾î ±¸Á¶¸¦ Ãß°¡ÇÒ ¼ö ÀÖ´Ù.
   3. º¹ÀâÇÑ °è»êÀ» ±¸ÇöÇÒ ¼ö ÀÖ´Ù.
   4. user°¡ Á¤ÀÇÇÑ Type, Function, OperationÀ» »ó¼ÓÇÒ ¼ö ÀÖ´Ù.
   5. Server ¿¡ ÀÇÇØ Trusted(Authentication °ü·ÃÀÇ ¶æ)µÈ°ÍÀ» Á¤ÀÇÇÒ ¼ö ÀÖ´Ù.
   6. »ç¿ëÇϱ⠽±´Ù.
¼³¸í

 PL/pgSQL Àº ´ë¼Ò¹®ÀÚÀÇ ±¸ºÐÀÌ ¾øÀ¸¹Ç·Î Å°¿öµå³ª Identifier µéÀº ´ë¼Ò¹®ÀÚ
 ±¸ºÐ¾øÀÌ È¥¿ëµÇ¾î ¾²ÀÏ ¼ö ÀÖ´Ù. 

PL/pgSQL Àº ºí·° ÁöÇâ¾ð¾îÀÌ´Ù. ºí·°Àº ´ÙÀ½Ã³·³ Á¤ÀǵǾîÁø´Ù.

    [ Label ]
    [ DECLARE  declarations ] 
    BEGIN  
            statements
    END;

ºí·°ÀÇ statements±¸¿ª³»¿¡ ¿©·¯°³ÀÇ sub-blockÀÌ »ý¼ºµÉ ¼ö ÀÖÀ¸¸ç ÀÌ´Â ¼­ºêºí·°³»ÀÇ º¯¼ö µéÀ» ¼­ºêºí·° ¿ÜºÎ·ÎºÎÅÍ ¼û±â±â À§ÇØ »ç¿ëµÇ¾îÁú¼ö ÀÖ´Ù. ºí·° ¾ÕºÎºÐÀÇ declarations±¸¿ª ¿¡¼­ ¼±¾ðµÈ º¯¼ö´Â function ÀÌ È£ÃâµÉ ¶§ ´ÜÁö Çѹø ÃʱâÈ­°¡ µÇ´Â °ÍÀÌ ¾Æ´Ï¶ó ºí·°À¸·Î ÁøÀÔÇÒ ¶§¸¶´Ù ¸Å¹ø µðÆúÆ® °ªÀ¸·Î ÃʱâÈ­µÈ´Ù.

PL/pgSQL ÀÇ BEGIN/END ¿Í Transaction(BEGIN; END;)À» À§ÇÑ µ¥ÀÌŸº£À̽ºÀÇ ¸í·É¹®°ú´Â ´Ù¸£´Ù´Â°ÍÀ» ÀÌÇØÇØ¾ß ÇÑ´Ù. ¶ÇÇÑ Function°ú Trigger Procedure ¿¡¼­´Â Æ®·£Àè¼ÇÀ» ½ÃÀÛ Çϰųª commit À» ÇÒ ¼ö ¾ø°í Postgres´Â ÁßøµÈ Æ®·£Àè¼ÇÀ» °¡Áú ¼ö ¾ø´Ù.

   --       : ÇÑ ¶óÀÎÀÇ ÁÖ¼®Ã³¸®
   /*   */  : ºí·° ´ÜÀ§ ÁÖ¼® ó¸®
example

   CREATE  FUNCTION  logfunc2(text,text,text)  RETURNS  datetime 
   AS ' 
       DECLARE  logtxt1  ALIAS  FOR  $1;
                logtxt2  ALIAS  FOR  $2;
                logtxt2  ALIAS  FOR  $3;
                curtime  datetime;
       BEGIN
          curtime :=''now'';
          INSERT  INTO  logtable  VALUES (logtxt1,logtxt2,logtxt3,curtime);
          RETURN  curtime;
       END;
  ' LANGUAGE 'plpgsql';
¼³¸í

$1,$2,$3 Àº ÇÔ¼öÀÇ ÀÎÀÚµé·Î¼­ ³ª¿­µÈ ¼ø¼­·Î¼­ ÂüÁ¶µÇ¾îÁø´Ù. DECLARE ÀÇ ALIAS FOR º¯¼ö $1 ¿¡ ´ëÇÑ º°¸íÀ» ¼³Á¤ÇÑ´Ù. À̷μ­ $1 ¿¡ ´ëÇÑ °¡µ¶¼ºÀÌ ³ô¾ÆÁú¼ö ÀÖ´Ù. curtime := ''now''; ´Â º¯¼ö curtime¿¡ ÇöÀçÀÇ ½Ã°¢°ªÀ»(''now'') ÇÒ´çÇÑ´Ù.":=" Àº º¯¼ö¿¡ °ªÀ» ÇÒ´çÇÒ¶§ ¾²ÀδÙ. ¸¶Áö¸·À¸·Î À§ÀÇ ÇÔ¼öÀÇ ¸®ÅÏ°ªÀÌ datetime À̹ǷΠdatetime ŸÀÔÀÇ º¯¼ö curtime À» ¸®ÅÏÇÏ°Ô µÈ´Ù.

4.2 PL/pgSQL 2

example 1

´ÙÀ½Àº ¿¹Á¦ÀÔ´Ï´Ù. Àû´çÈ÷ È­ÀÏ·Î º¹»çÇؼ­ ½ÇÇàÀ» ÇÏ¸é µË´Ï´Ù.

  DROP FUNCTION test1();
  DROP TABLE tab1;

  CREATE TABLE tab1 (
     id    int4,
     name  text
  );

  CREATE FUNCTION test1() RETURNS int4
  AS '
     DECLARE  
        var1  tab1.id%TYPE:=1;
        var2  tab1.name%TYPE;
        var3  var2%TYPE:=''nogada'';
     BEGIN
        INSERT INTO tab1(id,name) VALUES(var1,var3);
        RETURN  var1;
     END;
  '  LANGUAGE 'plpgsql';

  SELECT test1();
  SELECT * FROM tab1;
¼³¸í

À§ÀÇ ¿¹Á¦´Â DROP¸í·É¹®À¸·ÎºÎÅÍ ½ÃÀÛÇÑ´Ù. º°´Ù¸¥ ÀÌÀ¯´Â ¾ø°í ¾ÈÀüÇÑ Å×½ºÆ®¸¦ À§ÇØ ±âÁ¸¿¡ ÀÖÀ»Áö ¸ð¸¦ functionÀ̳ª table À» ¸ÕÀú »èÁ¦ÇÑ´Ù. DROP ¸í·É¾î·Î ÀÎÇÑ ¿¡·¯´Â ¹«½ÃÇصµ µÈ´Ù.FunctionÀÇ DECLARE ºÎºÐÀº º¯¼öÀÇ ¼±¾ð ±¸¿ªÀ¸·Î º¸¸é µÇ°Ú´Ù. var1 , var2,var3Àº º¯¼ö¸íÀÌ´Ù. tab.id%TYPE Àº var1 ÀÇ º¯¼öÇüÀ¸·Î¼­ tab.id ÀÇ ¼Ó¼ºÀ» ÂüÁ¶Çϸç À̼ӼºÀÇ ¹Ù·Î µÚÀÇ %TYPE ¿¡ÀÇÇØ ÁöÁ¤µÈ´Ù. ¶ÇÇÑ %TYPE Àº ¾ÕÀü¿¡ ¼±¾ðµÈ º¯¼öÀÇ ÀÚ·ãÇüÀ» ÂüÁ¶ ÇÒ ¼ö ÀÖ´Ù. var3 ´Â ¹Ù·Î Àü¿¡ ¼±¾ðµÈ var2 ÀÇ ÀÚ·áÇüÀ» ÂüÁ¶ÇÑ´Ù.

Trigger Procedure

PL/pgSQL Àº Æ®¸®°Å ÇÁ·Î½ÃÁ®¸¦ Á¤ÀÇÇϴµ¥ »ç¿ëµÇ¾îÁú ¼ö Àִµ¥ CREATE FUNCTION¹®À» »ç¿ë ÇÏ¿© »ý¼ºµÇ¾îÁø´Ù. »ý¼ºµÉ Æ®¸®°Å ÇÁ·Î½ÃÁ®´Â ´ëü·Î ÀÎÀÚ°¡¾ø°í opaqueÇüÀ» ¸®ÅÏÇÏ´Â ÇÔ¼ö ·Î¼­ »ý¼ºµÇ¾îÁø´Ù.

Æ®¸®°Å ÇÁ·Î½ÃÁ®·Î¼­ »ý¼ºµÈ ÇÔ¼ö¿¡´Â ¾à°£ÀÇ Æ¯¼öÇÑ º¯¼ö¸¦ °¡Áö¸ç ÀÌ´Â ÀÚµ¿À¸·Î »ý¼ºµÇ¾î Áö¸ç ´ÙÀ½°ú °°´Ù.

NEW        :  ROW ·¹º§ Æ®¸®°Å»ó¿¡¼­ INSERT/UPDATE ·Î ÀÎÇØ »õ·Î¸® »ý¼ºµÈ
              ROW ¸¦ À¯ÁöÇÏ´Â º¯¼ö·Î¼­ µ¥ÀÌŸŸÀÔÀº RECORD ÀÌ´Ù. RECORD
              ÇüÀº ¹Ì¸® ±¸Á¶È­µÇÁö ¾ÊÀº ROWTYPE·Î¼­ selectionÀ̳ª insert
              ,update ½Ã °á°ú·Î »ý¼ºµÈ ÇϳªÀÇ row ¸¦ À¯ÁöÇÏ´Â ÇüÀÌ´Ù.
OLD        :  new ¿Í ´ëÁ¶µÇ´Â º¯¼ö·Î¼­ UPDATE³ª DELETEÇü À¸·Î ÀÎÇØ º¯°æ
              µÇ±â ÀüÀÇ ROW¸¦ À¯ÁöÇÏ´Â º¯¼öÀÌ´Ù.
TG_NAME    :  µ¥ÀÌŸ ŸÀÔÀº NAME ÀÌ°í ½ÇÁ¦·Î ±âµ¿µÈ Æ®¸®°ÅÀÇ À̸§¿¡ ´ëÇÑ
              º¯¼öÀÌ´Ù.
TG_WHEN    :  textÇüÀÌ°í BEFORE³ª  AFTER¸¦ °¡Áø´Ù. 
TG_LEVEL   :  textÇüÀÌ°í ROW³ª STATEMENT¸¦ °¡Áø´Ù.
TG_OP      :  textÇüÀÌ°í INSERT³ª UPDATE³ª DELETE ¸¦ °¡Áø´Ù.
TG_RELID   :  oidÇüÀÌ°í(Object ID) Æ®¸®°Å¸¦ ±âµ¿½ÃÅ°´Â Å×À̺íÀÇ Object ID
              ÀÌ´Ù.
TG_RELNAME :  nameÇüÀÌ°í Æ®¸®°Å¸¦ ±âµ¿½ÃÅ°´Â Å×À̺íÀÇ name À» °¡Áö´Â º¯¼ö
              ÀÌ´Ù.
TG_NARGS   :  IntegerÇüÀÌ°í Æ®¸®°Å ÇÁ·Î½ÃÁ®¿¡ ÁÖ¾îÁö´Â ÀÎÀÚÀÇ °³¼öÀÌ´Ù.
TG_ARGV[]  :  array of text ÇüÀÌ°í Æ®¸®°Å ÇÁ·Î½ÃÁ®¿¡ ÁÖ¾îÁö´Â ÀÎÀÚµéÀ» 
              °ªÀ¸·Î °¡Áö´Â ÅؽºÆ® ¹è¿­ÇüÀÇ º¯¼öÀÌ´Ù.

4.3 ¿¹Á¦

´ÙÀ½À» È­ÀÏ·Î ¸¸µé¾î ½ÇÇàÇغ¸¼¼¿ä.

-------------------------------------------------------Cut here !!    
    DROP  TRIGGER   emp_stamp  ON  emp;
    DROP  FUNCTION  emp_stamp() ;
    DROP  TABLE  emp;


    CREATE  TABLE  emp(
      empname     text,
      salary      int4,
      last_date   datetime,
      last_user   name
    );


    CREATE  FUNCTION  emp_stamp()  RETURNS  OPAQUE
    AS '
     BEGIN
     
       IF  NEW.empname  ISNULL  THEN
          RAISE  EXCEPTION ''empname cannot be NULL value'';
       END  IF;
       
       IF  NEW.salary  ISNULL  THEN
          RAISE EXCEPTION ''% cannot have NULL salary'', NEW.empname ;
       END  IF;
       

       IF  NEW.salary  <  0  THEN
         RAISE  NOTICE ''% cannot have a negative salary'', NEW.empname ;
       END  IF;


       --NOTICE TEST
       RAISE NOTICE ''TRIGGER NAME : %'',TG_NAME ;
       RAISE NOTICE ''TRIGGER LEVEL : %   TRIGGER OPERATION : %'',TG_LEVEL , TG_OP;

       --EXCEPTION TEST
       RAISE EXCEPTION ''TRIGGER WHEN : %'',TG_WHEN;
       RAISE NOTICE ''TRIGGER LEVEL : %   TRIGGER OPERATION : %'',TG_LEVEL , TG_OP;


       NEW.last_date := ''now'';
       NEW.last_user := getpgusername();
       RETURN  NEW;
     END;
    ' LANGUAGE 'plpgsql';


    CREATE  TRIGGER  emp_stamp  AFTER  INSERT  OR  UPDATE  ON  emp
     FOR  EACH  ROW  EXECUTE  PROCEDURE  emp_stamp();


    INSERT  INTO  emp(empname,salary)  VALUES('nogadax',20);
    INSERT  INTO  emp(empname) VALUES('winob');
    INSERT  INTO  emp(salary)  VALUES(10);
    INSERT  INTO  emp(empname,salary)  VALUES('diver',30);
    INSERT  INTO  emp(salary)  VALUES(-20);


    SELECT  *  FROM  emp;
 
 --------------------------------------------------------------------------End !!
¼³¸í

RAISE´Â ¸Þ½ÃÁö¸¦ ´øÁö´Â °ÍÀÔ´Ï´Ù. EXCEEPTIONÀº Æ÷½ºÆ®±×·¹½ºÀÇ DEBUG·¹º§·Î¼­ µ¥ÀÌŸº£À̽º¿¡ log ¸¦ ³²±â°í Æ®·£Àè¼ÇÀ» ÁßÁöÇÑ´Ù. ´Ù¸¥ Å°¿öµå·Î NOTICE°¡ ÀÖ ´Âµ¥ ÀÌ°ÍÀº µ¥ÀÌŸº£À̽º¸¦ ÀÛ¼ºÇÏ°í À̸¦ Ŭ¶óÀ̾ðÆ®ÃøÀ¸·Îµµ Àü¼ÛÇÑ´Ù.

    RAISE EXCEPTION ''% cannot have NULL salary'', NEW.empname ;

À§ÀÇ ¹®¿¡¼­ '' ¿Í '' »çÀÌÀÇ % ´Â NEW.empname ÀÇ °ªÀ» Ãâ·ÂÇÑ´Ù.

      CREATE  TRIGGER  emp_stamp  AFTER  INSERT  OR  UPDATE  ON  emp
       FOR  EACH  ROW  EXECUTE  PROCEDURE  emp_stamp();

NEW.empnameÀÇ NEW´Â RECORDŸÀÔÀ¸·Î¼­ Æ®¸®°ÅÀÇ À̺¥Æ®ÀÇ ¿øÀÎÀÌ µÇ´Â emp ÀÇ ±¸Á¶¸¦ °¡Áö¸ç NEW ÀÇ °ªÀº eventÀÇ °á°ú·Î¼­ Ãß°¡µÇ°Å³ª º¯°æµÈ ÇàÀ» °¡Áø´Ù.

Á¤¸®

Declaration : ¼±¾ðºÎ

name [CONSTANT] type [NOT NULL] [DEFAULT | :=value]

      example )
         DECLARE 
             var_a  int4  DEFAULT  5;

    --var_a  º¯¼öÀÇ  DEFAULTÀÇ °ªÀº  5ÀÌ´Ù.
             
name class%ROWTYPE

      example ) 
         DECLARE 
              var_a  test_table%ROWTYPE;
              
   var_a º¯¼ö´Â test_table ÀÇ Å×ÀÌºí ±¸Á¶¸¦ °¡Áø´Ù.
name RECORD

      example ) 
         DECLARE
            var_a  RECORD ;
            
    ƯÁ¤ Å×À̺íÀÇ ±¸Á¶¸¦ °¡ÁöÁö ¾Ê°í selection ÀÇ °á°ú¿¡ 
    ´ëÇÑ ±¸Á¶¸¦ °¡Áú ¼ö ÀÖ´Ù.(NEW,OLD)§  
name ALIAS FOR $n;

             $n ¿¡ ´ëÇÑ º°Äª
         
RENAME oldname TO newname

            oldname¸¦  newname·Î ¹Ù²Þ
Data Type : ÀÚ·áÇü

      
Postgres-BaseType : Æ÷½ºÆ® ±×·¹½ºÀÇ ±âº» ÀÚ·áÇü( int4,integer,text,char,..)

variable%TYPE     

class.field%TYPE
Expression

      
      Select expression
Statement : 󸮹®Àå

Assignment : °ªÀÇ ÇÒ´ç

      
        identifier :=expression;
  
        SELECT  expressions  INTO  target  FROM ...
      
        PERFORM  query  : Calling another function  
    
        RETURN  expression;

        RAISE  [NOTICE | EXCEPTION]  '' message % '',variable
       
Á¦¾î¹®

     
        IF  expression  THEN
           statements
        [ELSE  statements]
        END  IF;


        [label]
        LOOP  statements  END  LOOP;


        [label]
        WHILE  expression  LOOP  statements  END  LOOP;


        [label]
        FOR  name  IN  [REVERSE]  expression  LOOP  statements  END  LOOP;


        [label]
        FOR  record | row  IN  select_clause  LOOP  statement
        END  LOOP;


        EXIT  [label]  [WHEN  expression];

´ÙÀ½ ÀÌÀü Â÷·Ê