The following Figure shows the meta-model based on a subset of these requirements.<br/>The AssociationSpecification “validFor” attribute was intentionally left without a data type to make implementation in a database simpler. Also, the multiplicity of the “AssociationSpecificationDefinedBy” multiplicity for the “AssociationRoleSpecification” role was set to 2. This only permits binary (two entities involved) associations.<br/>The requirements could be used to identify more attributes that further define the association entities. In fact, there are more entities that could be added to the model to support stereotypes, constraints, and so forth, as shown in the following Figure. That is why the introduction to these meta-modeling sections mentioned that the models/thoughts described here are just initial.<br/>