Re: Multiple user row-level permissions

"Yip" <yip_at_lanarchy.com> schreef in bericht news:2956df5d.0208060613.28ada9fd_at_posting.google.com...
> Hello,
>
> I've been wrestling with a problem for the past while, and was curious
> if anyone here may have some insights to help make some headway.
>
> Basically, I'm trying to come up with a method of having row-level
> permissions in a table for more than one user. The potential exists
> for several hundred people to be able to access a particular row. In
> addition, users may be added or removed dynamically, which would force
> the corresponding rows to be updated.
>
> I looked at the method of appending a username field at the end of
> each row, using a delimiter to separate the different ids, but that
> doesn't seem to be applicable, owing to the fact that the size of the
> field would quickly become unmanageable (not to mention the
> performance hit of searching each row's field).
>
> Another more promising approach was assigning each user a unique prime
> number, and using the product of all of the users with permission as
> the field value. Although that number quickly becomes huge, it would
> be possible to use a division method to find permissions. There are
> some performance issues here, too. I've also toyed with an array of
> bits, using XOR operations and salts to generate the final bit hash.
> I don't know enough of the underlying crypto theory to realistically
> implement this, though, and it doesn't seem as though it would be that
> efficient to implement for each row.
>
> It seems like there should also be a method using a series of lookup
> tables as well. There are several fields which could potentially be
> used to group similar sets of data, while still having the possibility
> that any arbitrary row could be accessed by only one particular user.
> In general, the sets of users with permissions for a row will be
> similar, which would reduce the number of lookup keys significantly.
> It feels like I'm still missing something about this approach, though.
>
> Anyway, if anyone has thoughts and/or comments, or has done anything
> like this, I'd be much obliged if you could provide some insights.
>
> Thanks!
>
> - Nate

make 3 tables:
users, basic table, 'has access to'
'has access to': userid, recordid
Is there a way to create usergroups? Received on Tue Aug 06 2002 - 18:21:24 CEST