if not exists (select * from sys.tables where object_id = object_id(N'dbo.ConnectionGroup'))
    create table dbo.ConnectionGroup
    (
        ID int not null IDENTITY(1, 1) constraint PK_ConnectionGroup primary key 
        ,ConnectionID uniqueidentifier not null constraint FK_ConnectionGroup_ConnectionID foreign key references dbo.Connections(ID) on delete cascade
        ,GroupName nvarchar(256) not null
        ,constraint UIX_ConnectionGroup_ConnectionID_GroupName unique (ConnectionID, GroupName)
    )