Message-ID: <44270BF6.6080109@obviously.com>
Date: Sun, 26 Mar 2006 13:47:34 -0800
From: Bryce Nesbitt <bryce1@obviously.com>
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To: pgsql-sql@postgresql.org
Subject: Bitfields always atomic? Other way to store attributes?
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Dear List;

If I have two threads modifying the same "bit" field:
    thread1=> update table set bf=bf | '01000'
    thread2=> update table set bf=bf | '10000'
Will this operation always be safe (e.g. result in bf='11000')?  Or must
I wrap things in
explicit transactions?

My application is to give attributes to an address table.  But maybe
there is a better way?

I want to mark each addresses with attributes, e.g. the person may be a
"friend", "on my holiday card list", "owe me money", be an "employee", a
"volunteer on the xxx project", or none of the above.

I could assign each role a bit.

Or, create a string field: "Friend,Money, Emp,VolXXX".

Or, create related tables:
        friend_pk,         address_id
        cardlist_pk,       address_id
        money_pk,        address_id,    amount_owed
        volunteer_pk,    address_id

Any thoughts?

                        -Bryce Nesbitt

      

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