[Opensim-users] Uniqueness in MySQL 'useraccounts'

[Kevin Buckley]

Hi Karen

As far as I understand (or can guess!), the concept is that the AV UID
(PrincipalID) and asset UID's are created by using a timestamp variant of
UUID (so I'm using the one provided conveniently by MySQL which provides
temporal separation plus 48 bit random, spatial separation).  So that takes
care of the nuts and bolts.

And yes I can see that, in the hypergrid case, there is the issue of names
which are unique within each OS implementation (which I'm trying to deal
with now) but not able to be guaranteed unique everywhere as they are chosen
by people who are not known for their randomness.  I am assuming that the
combination of locally enforced, unique FirstName+LastName plus host ID,
provides a globally unique name scheme even in the hypergrid scenario.

Is that correct?

Is the host ID you referred to, the ServiceURL field in the same table
(useraccounts)?

Kevin

-----Original Message-----
From: opensim-users-bounces at lists.berlios.de
[mailto:opensim-users-bounces at lists.berlios.de] On Behalf Of Karen Palen
Sent: 05 March 2012 16:10
To: opensim-users at lists.berlios.de
Subject: Re: [Opensim-users] Uniqueness in MySQL 'useraccounts'

I suspect the answer is that you need more information than just those
two fields.

I am thinking of the fairly common case in Hypergrid usage where two
avatars have the same name, distinguished only by the field that tells
their host system.

I have used this for testing on many occasions.

Karen

On 03/05/2012 04:45 AM, Kevin Buckley wrote:
> Hi - Thanks for the quick response.
>
> I understand the reasons why PrincipalID is the Primary Key and hence
should
> be unique (and I now realise my original question was malformed).
>
> The actual question is: Why isn't 'Name' (the composite key including
> FirstName and LastName) defined as Unique?
>
> Defining it as Unique certainly works and causes MySQL to throw Error 1062
> in response to an attempt to create  a duplicate FirstName/LastName entry
> which is the (my) required behaviour.
>
> So I am wondering why 'Name' isn't defined as Unique when the database
> tables are created (or upgraded) by Opensim, given that it goes to the
> trouble of defining it in the first place!
>
> Thanks.
>
> -----Original Message-----
> From: opensim-users-bounces at lists.berlios.de
> [mailto:opensim-users-bounces at lists.berlios.de] On Behalf Of M.E. Verhagen
> Sent: 04 March 2012 23:42
> To: opensim-users at lists.berlios.de
> Subject: Re: [Opensim-users] Uniqueness in MySQL 'useraccounts'
>
> the PrincipalID field is already the primary key.
>
> There can be only one primary key.
>
> This uuid key is the unique identifier on wich an avatar is idenified.
>
> When you write you own member system with direct database manipulation
> than you should check if the avatar is unique or else you will end up
> with more than one avatar name attached to an uuid.
>
>
>
> 2012/3/4, Kevin Buckley <kevin at buckley70.freeserve.co.uk>:
>> I hope this is not covering old ground.  I'm playing with a member system
>> for standalone OpenSim and I'm trying to decide the best way to deal with
>> the FirstName/LastName uniqueness issue (as my sign-up process allows
>> multiple, concurrent users).
>>
>>
>>
>> I notice that the default useraccounts table has a composite key called
> Name
>> (which consists of FirstName and LastName).  But it isn't defined as a
>> primary key.  So duplicate name inserts are not trapped as a result of
> that
>> (I believe that is the reason, anyway).
>>
>>
>>
>> Does anyone know if there is a reason 'Name' is not defined as a primary
>> key?  Is there a problem with making it so?
>>
>>
>>
>> I have other ways I can deal with this but trapping it at the
useraccounts
>> table insert would be the best way.
>>
>>
>>
>> Thanks.
>>
>>
>
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