Working in Database Diagrams

Database diagrams show a submodel of the database schema.

Database diagrams represent a submodel of the database schema. Database tables are shown as nodes and foreign keys as edges. Database views can also be displayed as nodes and their From clauses as edges.

Innovator for Information Architects uses IDEF1X notation.

The IDEF1X edge notation of the foreign keys is calculated from the context as follows.

• A solid edge shows an identifying foreign key. A foreign key is identifying if all its columns are also included in the primary key of the table.

• Non-identifying foreign keys have a dashed edge.

• The black circle is always on the table which owns the foreign key. The other table owns the referencing key.

• If the columns of the foreign key form the entire primary key of the table, it is labeled with a 'Z' (for 'zero or one'), as each instance in the table with the referencing key can be referenced by maximum one instance from the table with the foreign key.

• The white diamond on the referencing table indicates that it is an optional foreign key. A foreign key is optional if at least one of its columns may have no value.