Multiplicity of Associations

The multiplicity of an association represents how many rows there are in one view for each row of the other.

For example, let us say that you create an association between the view customer and the view order, the multiplicity at the endpoint customer (role name orders) is 1 and at the endpoint order (role name customer) is *. This indicates that for each row of the customer view there are zero, one or more rows in the order table; and for each row in the order view there is one and only one row in the view customer.

  • 0..1 indicates a multiplicity of 0 or 1.
  • 1 indicates a multiplicity of 1.
  • * indicates a multiplicity of 0 or more.
  • + indicates a multiplicity of 1 or more.