RE: % Negation Character

Hi Citlali,  

Unforetunately, AskTom, which has some great examples, seems to be down at the moment. However, I don't think you want to use the UTL_RAW stuff.  

There is the bitand() function, which is built-in to Oracle, and which is now documented, since 9i, I think.  

From that, you can build a simple bitor(): CREATE OR replace FUNCTION bitor( x IN NUMBER, y IN NUMBER ) RETURN NUMBER AS BEGIN
    RETURN x + y - bitand(x,y);
END;
/
And, once you have both bitand() and bitor(), you can build a bitxor(): CREATE OR replace FUNCTION bitxor( x IN NUMBER, y IN NUMBER ) RETURN NUMBER AS BEGIN
    RETURN bitor(x,y) - bitand(x,y);
END;
/    

Finally, for One's complement, you can xor the number with all 1's. Here's the code for bitcomplement():
create or replace function bitcomplement(x in number, y in number) return number as begin
  return bitxor(x,power(2,y)-1);
end;
/  

So, you can do something like:
SQL> select bitcomplement(2,4) from dual; BITCOMPLEMENT(2,4)

                13

Note that the second argument to bitcomplement is how "wide" the bitfield should be. In this case, it's 4, if you're expecting 13. Note that the value of the one's complement will depend on how many 1's you're xoring against.  

Finally, thanks to Connor McDonald for the bitor() and bitxor() functions. The bitcomplement() function is my own creation.  

-Mark

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________________________________

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Guerrero, Citlali (GE, Corporate, consultant)
Sent: Monday, June 18, 2007 11:07 AM
To: Nigel Thomas
Cc: oracle-l
Subject: Re: % Negation Character


Hi Nigel,

    Thanks for the tip, however, as you mention on your email, I'm facing some troubles with the data types,  I mean if  I perform:

          raw_value := utl_raw.cast_from_number('2'); -- This is equal to c103
          
   and then I try to get the complement or negative value with this:

        select select utl_raw.bit_COMPLEMENT('c103') from dual;
   I get the value:

 UTL_RAW.BIT_COMPLEMENT('C103')    
 --------------------------------- 
 3efc
          
   And when I try to perform this: SELECT utl_raw.cast_to_number('3efc') FROM dual 
I got the result:  

UTL_RAW.CAST_TO_NUMBER('3EFC')    
 --------------------------------- 
 -105  

What I'm expecting is: 13 ...


   Do you know or have any clue about this??? I really appreciate the help


Regards Citlali
Nigel Thomas escribió: 

	Citali


	>    I'm migrating from Sybase to Oracle, on Sybase I had a function with

	>    update XYZ

	>    set flag = flag &~4589

	
	You can use BITAND(arg1, arg2) - see the SQL reference for more information. Shame there's no BITOR to go with it... See also UTL_RAW package and functions BIT_AND, BIT_OR, BIT_XOR and BIT_COMPLEMENT. You just need to be careful with datatypes, I seem to remember.
	 
	I played with UTL_RAW quite recently, but on a previous site so I don't have it to hand, sorry.
	 
	HTH
	 
	Regards Nigel
	
	 

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