Yes, there is a way to add Primary & Foreign Keys in pgAdmin.
Tested in pgAdmin III Ver.1.16.1 (Windows 7)
- Select the table you want
- Ctrl+Alt+Enter or right-click / Properties
- Select “Constraints” tab
- At the left-bottom side of the form you will see the option “Primary Key”
- Click add
- Select “Columns” tab
- Select the column you want as a key
- Click add
And you are all set.
You can fill more things if you want, but now you know how to get there.