Project scheduling software (scriptable, cross-platform, and open source)
GanttPV Home
Why GanttPV? Help Scripts Server Developer
Object Role Modeling

How to get started with Object Role Modeling in GanttPV

This page is primarily a quick start for people who are familiar with Object Role Modeling, but new to GanttPV. If you are already familiar with GanttPV you might prefer to start with the ORM Quick Start menus in GanttPV.

To create an ORM diagram:

  1. Start the GanttPV application
    • On Windows, Start -> All Programs -> GanttPV -> GanttPV
    • On Macintosh, double-click on GanttPV icon
  2. Add the ORM reports to the report menu
    • Select the menu:
        Scripts -> Object Role Modeling -> Install ORM Diagram
    • (If Object Role Modeling is not listed in the Scripts menu, use the Select Scripts Directory option first.)
  3. Add an ORM diagram
    1. Select project named New Project
    2. Click the New Report toolbar button (second from left)
    3. Select ORM Diagram and click OK
    4. Open the diagram by double-clicking on ORM Diagram row
  4. Browse the quick start information from the Help menu:
    1. Open ORM Quick Start in the Help menu
    2. Click on the tabs and review the help contents
    3. Be sure to use the hints in the Shortcuts tab


Almost all of the ORM 2 notation is implemented:

  • Object (Entity and Value) Types
  • Fact Types
  • Roles and role names
  • Uniqueness constraints (internal and external)
  • Role constraints (subset, equality, exclusion)
  • Subtypes and subtype constraints
  • Ring constraints
  • Notes

Partially implemented

The Rmap (ORM to relational database mapping) and SQL generation are only partially implemented, but include setting an implementation baseline and migration assistance. They are offered as a preview of what is to come. (We felt that the value of the ORM/Rmap would be easier to understand through experimentation with a partial implementation.)

Other current limitations:

  • Graphics objects can appear in only one diagram (tends to limit models to one diagram)
  • Supports copy and paste only of graphics into MS Word (MS Windows only)
  • Notes attach only to Object Types and Fact Types
  • Only one reading may be entered per fact type
  • Diagram does not automatically update when data is changed via another report (close and reopen diagram to refresh when needed)


In the notation :

  • Value and cardinality constraints (use Notes instead)
  • Sample data

Some features are not implemented:

  • Verbalization of constraints is not implemented.
  • The constraint language is not implemented.