Configuring, manipulating, and reusing ORM models

This chapter discusses the configuration, manipulation, and reuse of object-role modeling (ORM) models. ORM modeling solution tool applies various default settings to determine how it displays the user interface and how it reacts to certain user commands. These settings can be changed to suit the personal preferences by entering personal choices in the Database Modeling Preferences dialog. To access this dialog, Database > Options > Modeling should be chosen from the main menu. The dialog includes Fact Editor and ORM Diagram panes for setting ORM preferences. The other two panes deal with preferences for the logical modeling solution. The Object type name field allows controlling the base default name for new object types. By default, this is “Object.” The Append ordinal check box is used to append numbers 2, 3, etc., to the default names of second and later object types. In an ORM schema, object types may be connected by predicates and/or subtype relationships. Graphically, a predicate is depicted as a named sequence of one or more role boxes and a subtype relationship is depicted as an arrow from subtype to super type. Each object type is either an entity type or a value type and is defined in exactly one model. It is possible to define an object type or predicate in one model and then reference it from one or more other models.