Jeff,
Why not have the primary key be login name, and have another field
which is the lowercased name. Then you can create a unique database
index on each field.
Jeff Schnitzer wrote:
>
> Hi everyone, I am dumbfounded by what I imagine should be a common and
> many-times-solved problem. I would love to know how people are
> addressing this situation:
>
> I have a more-or-less typical membership-based website. Users can sign
> up and create accounts; users can choose their unique login name.
>
> I've modeled the user as a CMP entity bean called Member. Now, what to
> choose as the primary key?
>
> The natural option (and the one I chose) was to use the login name as
> the primary key. But I want to make this key case-insensitive (there
> cannot be both "Bob" and "bob"), and there doesn't seem to be a natural
> way of doing this.
>
> I have a feeling it will work if a) my PK class does case-insensitive
> comparisons and b) I instruct the my container to use more interesting
> sql for findByPrimaryKey(). But I'm not sure that (b) is something I
> will be able to do for all containers. Actually, I'm not even sure that
> this is something I'll be able to do for my own container. Is this the
> "correct" solution to the problem, and I should stop worrying about it?
>
> Another approach which has some significant appeal is to use a generated
> integer primary key independent from the name. Now the problem is, how
> do I guarantee that two users do not create accounts nearly
> simultaneously with the same login name? It seems to me that simply
> ensuring that findByName() returns nothing and then saving the value
> opens up the opportunity for a race condition. How can I protect
> against this?
>
> Ok, I could add another entity/table, "AllocatedName" which simply
> stores the downcased version. Or I could use a singleton RMI server to
> provide a locking service. But isn't this a little excessive? There
> has got to be an easier way... and given the number of sites out there
> that work like mine, this must have been done dozens of times already.
> What am I missing?
>
> Thanks,
> Jeff Schnitzer
>
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