ADISC conceptual data model

overview A conceptual data model is a clear and accurate visual representation of relevant business rules and concepts associated with the business area under consideration from a data perspective. The model serves as a common frame of reference to define the scope of a new system and serves as the basis for moving forward with detailed business systems analysis and development of a business system design specification.

A conceptual data model is comprised of entity types and relationships. An entity type represents a single business concept (e.g., an enclosure, an animal group, an individual animal, etc.) and is defined by a name and description. On the data model, an entity type appears as a rectangle. A relationship depicts a business-based association between two entity types and appears as a solid or dashed line on the data model.

Every relationship has a notation, also called cardinality, that defines how many instances of each entity type can be related to one another. For example, it depicts whether an animal group can be related to only one taxonomy or multiple taxonomies. The symbols that define cardinality include:

• A single line (--|--) that crosses the relationship represents a single mandatory relationship (e.g., an animal group must be classified as only one taxonomy)
• A single line with a "crow’s foot" (--|<) represents a mandatory one or many relationship (e.g., animal group must belong to one or more taxonomies)
• An "O" with a "crow’s foot" (--o<) represents an optional one or many relationship (e.g., an animal group may or may not have one or many taxonomies)
• An semicircle with an "X" in it represents a subcategory (e.g., a business party represents either a zoo, an aquarium, an association, a dealer, etc.)

The appropriate business rule in question will dictate which symbol is used.

To read the model, simply look at each relationship and consider the cardinality on both ends of that relationship. For example, the model fragment below depicts that business rule that:

§ A single animal group must belong to only one taxonomy

§ A single taxonomy may or may not related to one or many animal groups

---------------------- -----------------

| animal group |->o-----------------|--| taxonomy |

---------------------- -----------------