Using a bitwise flag for a primary key?
I am designing a database and was thinking about the need for a one to many relationship. Traditionally I have done the normal PK (as a GUID) and set up the relationship, but I was wondering instead if doing that why not use a bitwise flag as the PK. 

The relationship would be lost but the data itself would describe the relationship.

Example - I have a table of groups and a table of users. Users can have 1 or more groups:  

    +------------------------+
    | Groups                 |
    +------------------------+
    | PK      | Display Name |
    +---------+--------------+
    | 1       | Group A      |
    | 2       | Group B      |
    | 4       | Group C      |
    +---------+--------------+

    +------------------------+
    | Users                  |
    +------------------------+
    | Name    | Groups       |
    +---------+--------------+
    | Fred    | 1            | // Fred is only in Group A
    | Jim     | 3            | // Jim is in Groups A & B
    | Sam     | 7            | // Sam is in all Groups
    +---------+--------------+

Thoughts, comments and suggestions on this design please?


Using a bitwise flag for a primary key?
===

I am designing a database and was thinking about the need for a one to many relationship. Traditionally I have done the normal PK (as a GUID) and set up the relationship, but I was wondering instead if doing that why not use a bitwise flag as the PK. 

The relationship would be lost but the data itself would describe the relationship.

Example - I have a table of groups and a table of users. Users can have 1 or more groups:  

    +------------------------+
    | Groups                 |
    +------------------------+
    | PK      | Display Name |
    +---------+--------------+
    | 1       | Group A      |
    | 2       | Group B      |
    | 4       | Group C      |
    +---------+--------------+

    +------------------------+
    | Users                  |
    +------------------------+
    | Name    | Groups       |
    +---------+--------------+
    | Fred    | 1            | // Fred is only in Group A
    | Jim     | 3            | // Jim is in Groups A & B
    | Sam     | 7            | // Sam is in all Groups
    +---------+--------------+

Thoughts, comments and suggestions on this design please?

