This seems like a simple query to me. Correct me if I am wrong but as
I understand it you want to get a list of SwReleases that a user has
access to. Would something like this not work
SELECT s.ID, s.Name
FROM SwRelease as s
WHERE s.ID IN (
FROM GroupSwRel -- this table is the group to SwRelease relation ship
WHERE GroupID IN (
FROM UserGroupRel -- this table is the user to group relationship.
WHERE UserID = 'someuserid'))
I've never done a query with a sub query in a sub query but it seems
like it should work to me. In fact, if I'm not mistaken you may be able
to rewrite this just using joins.
David T. Ashley wrote:
> I'm implementing a software release database. Users may aribtrarily be
> members of groups (a many-to-many mapping), and each software release may
> contain multiple files.
> I'd like to allow users the maximum flexibility in deciding who may view
> what software releases. The most obvious approach is to allow
> in the form of "Release X may be viewed by Users in Group Y or Group
> Z", per
> In this case, the database design would be something like:
> [Users] (many:many) [Groups] (many:many) [SwReleases] (1:many) [Files]
> The many:many relationship between groups and software releases
> specifies a
> Boolean function, of the form "is in Group X or is in Group Y or ...".
> Since one knows the user who is logged in (for a web database), one
> can do
> an outer join and quickly find all the software releases that the user
> view. I believe one can do it in O(log N) time.
> However, the Boolean function is of a fairly special form ("is in
> Group X or
> is in Group Y ..."). This is the only form where it seems to
> translate to
> an SQL query naturally.
> Here is my question:
> Is there any interesting way to structure a database so that other
> forms of
> permissions can be specified and translate directly into SQL queries?
> For example, what if, for a software release, one says, "to view this
> software release, a user must be in Group X or Group Y, but not in
> Group Z
> and not user Q"? Is there a database structure and a corresponding
> O(log N)
> query that will quickly find for a given user what software releases
> may be
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