The following conventions apply to the diagrams in both the high-level EIM and the BAIM diagrams.
Subject Area entities
– these are entities that are central to the subject area described by the diagram. They will be coloured and will have solid line borders.
External entities
– these are entities that are ancillary to the subject area described by the diagram. They will be white and will have broken line borders.
When considering the diagrams you should note the following:
These diagrams represent a high-level conceptual view of the data structure underlying DOH business. As such many-to-many relationships are acceptable, and are resolved only if necessary for the clarity of the conceptual view.
Not all external relationships from each Subject Area entity are shown on the diagrams. This is done to keep the diagrams reasonably uncluttered. The text of the model includes all relationships, and in some cases a more detailed diagram is available for entities with a lot of relationships.
Relationships between external entities on a diagram are usually not illustrated.
When exclusion arcs include relationships that are not pertinent to the diagram, the arc is shown even though only one relationship is drawn, to indicate that there is mutual exclusivity.
When an external entity that is a subtype is shown on a diagram, the supertype of the entity is shown only if this aids the clarity of the diagram.
