Re: Two tables with non-unique column

[Phillip Ward]

Change the Primary Key on T2 to be a composite key on both OrganisationId and UserId.

create table T2 
( organisationId integer not null 
, userId integer not null 
, primary key ( organisationId, userId ) 
) ;

You probably want foreign keys back to T1 and the organisations "master" table as well.

Regards,
Phill W.