Next we must define the roles we need. Start creating a new Role type: on the Graph Tool’s Types page, move the cursor into the Roles list, press the right mouse button, and select Add New... from the popup menu to open a new Role Tool. The roles for our Family relationship are easy to create, as they do not require any properties or symbols. So, to create a Parent role, just enter ‘Parent’ in the top-most field (Figure 3-17) and press Save.

We can keep this Role Tool open to create and add the Child role in the same way. We just need to tell it that we are creating a new type, rather than changing the name of the existing type: press the New button in the Role Tool toolbar or select Role | New from the menu bar. Then enter ‘Child’ in the Name field and press Save and Close. This is also a good time to commit our work again.