Data Modeling: Supertype / Subtype

Question

Looking to figure out the proper way to model the below requirements.

1. There are 3 types of “parties” to be concerned with, a Fan, a Band, and a BandMember.

Answer 1

I think this is simpler than you think. You've got two objects - Band and Person, and they can be connected in two different ways, either as a fan or a member. Here is a quickie db script with no foreign keys or anything:

CREATE TABLE [dbo].[XREFBandMembers](
    [MemberID] [int] NOT NULL,
    [BandId] [int] NOT NULL,
 CONSTRAINT [PK_XREFBandMembers] PRIMARY KEY CLUSTERED 
(
    [MemberID] ASC,
    [BandId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[XREFBandFans](
    [FanId] [int] NOT NULL,
    [BandId] [int] NOT NULL,
 CONSTRAINT [PK_XREFBandFans] PRIMARY KEY CLUSTERED 
(
    [FanId] ASC,
    [BandId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[People](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](100) NOT NULL,
 CONSTRAINT [PK_People] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[Bands](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](50) NOT NULL,
 CONSTRAINT [PK_Bands] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

As for the relationship specific attributes, you can place them in the XREF tables, e.g., FanClubMembershipNumber goes in XREFBandFans.