RE: Using bits to store information in the database.

From: Chelur, Jayadas {PBSG} <jayadas.chelur_at_pepsi.com>
Date: Wed, 07 May 2003 08:06:40 -0800
Message-ID: <F001.005926AF.20030507080640@fatcity.com>

most common use of bit-logic is to combine multiple "attributes" which may occur in combinations. e.g. in UNIX read-write-execute permissions as in chmod can be defined as ...  

READ        100    (4)
WRITE       010   (2)

EXECUTE 001 (1)   which would accomodate all 6 combinations of R-W-X into 3 bits. the point is they COULD EXIST IN ANY COMBINATION ...  

in this case, i agree with raj completely regarding use of integers. first of all,
"states" like "verified" and "non-verified" , "confirmed" and
"non-confirmed"

does not seem to co-exist ( at least, as far as their names go ). this itself does
not justify the use of bit-logic ( even before performance impact is considered ).  

moreover, if the "states" themselves transition in a particular order, use of
integers are much more suitable to track them. ( it gets "confirmed" only after
it is "verified" ... and so on and so forth )  

imho, storing bit-logic in columns should be the last resort, if at all ...    

-----Original Message-----
Sent: Wednesday, May 07, 2003 10:57 AM
To: Multiple recipients of list ORACLE-L

I think using integers rather than bits will be easier on your where clause. It might look nice, but it will probably be a killer for performance when you starting using bit logic in queries.  

I'd prefer but YMMV  

Verified         1
Non-Verified     2
Conformed        3
non-confirmed    4
Audited          5

Raj

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Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----
Sent: Wednesday, May 07, 2003 10:22 AM
To: Multiple recipients of list ORACLE-L

Looking for advise on storing bits in the Oracle database column. The scenario goes like this:  

define column statusFlag NUMBER(x)
statusFlag can represent the following:  

verified set to 1
nonverified set to 10
confirmed set to 100
non confirmed set to 1000
audited set to 10000  

I believe this gets my point accross.... So here are my questions:

What is the largest amount of bit I can set for a NUMBER(x)?  

How can one set and retrive the information in Oracle based on bits being set?  

Are there any draw backs from using too large of a NUMBER? I can guess one.. wasted space.    

Thanks in advanced,
-Lizz

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Author: Chelur, Jayadas {PBSG}
  INET: jayadas.chelur_at_pepsi.com

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Received on Wed May 07 2003 - 11:06:40 CDT